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PHP and COM> <Password Hashing
[edit] Last updated: Fri, 22 Jul 2011

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PHP and HTML

PHP and HTML interact a lot: PHP can generate HTML, and HTML can pass information to PHP. Before reading these faqs, it's important you learn how to retrieve variables from external sources. The manual page on this topic includes many examples as well. Pay close attention to what register_globals means to you too.

What encoding/decoding do I need when I pass a value through a form/URL?

There are several stages for which encoding is important. Assuming that you have a string $data, which contains the string you want to pass on in a non-encoded way, these are the relevant stages:

  • HTML interpretation. In order to specify a random string, you must include it in double quotes, and htmlspecialchars() the whole value.

  • URL: A URL consists of several parts. If you want your data to be interpreted as one item, you must encode it with urlencode().

Example #1 A hidden HTML form element

<?php
    
echo "<input type='hidden' value='" htmlspecialchars($data) . "' />\n";
?>

Note: It is wrong to urlencode() $data, because it's the browsers responsibility to urlencode() the data. All popular browsers do that correctly. Note that this will happen regardless of the method (i.e., GET or POST). You'll only notice this in case of GET request though, because POST requests are usually hidden.

Example #2 Data to be edited by the user

<?php
    
echo "<textarea name='mydata'>\n";
    echo 
htmlspecialchars($data)."\n";
    echo 
"</textarea>";
?>

Note: The data is shown in the browser as intended, because the browser will interpret the HTML escaped symbols. Upon submitting, either via GET or POST, the data will be urlencoded by the browser for transferring, and directly urldecoded by PHP. So in the end, you don't need to do any urlencoding/urldecoding yourself, everything is handled automagically.

Example #3 In a URL

<?php
    
echo "<a href='" htmlspecialchars("/nextpage.php?stage=23&data=" .
        
urlencode($data)) . "'>\n";
?>

Note: In fact you are faking a HTML GET request, therefore it's necessary to manually urlencode() the data.

Note: You need to htmlspecialchars() the whole URL, because the URL occurs as value of an HTML-attribute. In this case, the browser will first un-htmlspecialchars() the value, and then pass the URL on. PHP will understand the URL correctly, because you urlencode()d the data. You'll notice that the & in the URL is replaced by &amp;. Although most browsers will recover if you forget this, this isn't always possible. So even if your URL is not dynamic, you need to htmlspecialchars() the URL.

I'm trying to use an <input type="image"> tag, but the $foo.x and $foo.y variables aren't available. $_GET['foo.x'] isn't existing either. Where are they?

When submitting a form, it is possible to use an image instead of the standard submit button with a tag like:

<input type="image" src="image.gif" name="foo" />
When the user clicks somewhere on the image, the accompanying form will be transmitted to the server with two additional variables: foo.x and foo.y.

Because foo.x and foo.y would make invalid variable names in PHP, they are automagically converted to foo_x and foo_y. That is, the periods are replaced with underscores. So, you'd access these variables like any other described within the section on retrieving variables from external sources. For example, $_GET['foo_x'].

Note:

Spaces in request variable names are converted to underscores.

How do I create arrays in a HTML <form>?

To get your <form> result sent as an array to your PHP script you name the <input>, <select> or <textarea> elements like this:

<input name="MyArray[]" />
<input name="MyArray[]" />
<input name="MyArray[]" />
<input name="MyArray[]" />
Notice the square brackets after the variable name, that's what makes it an array. You can group the elements into different arrays by assigning the same name to different elements:
<input name="MyArray[]" />
<input name="MyArray[]" />
<input name="MyOtherArray[]" />
<input name="MyOtherArray[]" />
This produces two arrays, MyArray and MyOtherArray, that gets sent to the PHP script. It's also possible to assign specific keys to your arrays:
<input name="AnotherArray[]" />
<input name="AnotherArray[]" />
<input name="AnotherArray[email]" />
<input name="AnotherArray[phone]" />
The AnotherArray array will now contain the keys 0, 1, email and phone.

Note:

Specifying an arrays key is optional in HTML. If you do not specify the keys, the array gets filled in the order the elements appear in the form. Our first example will contain keys 0, 1, 2 and 3.

See also Array Functions and Variables From External Sources.

How do I get all the results from a select multiple HTML tag?

The select multiple tag in an HTML construct allows users to select multiple items from a list. These items are then passed to the action handler for the form. The problem is that they are all passed with the same widget name. I.e.

<select name="var" multiple="yes">
Each selected option will arrive at the action handler as:
var=option1
var=option2
var=option3
      
Each option will overwrite the contents of the previous $var variable. The solution is to use PHP's "array from form element" feature. The following should be used:
<select name="var[]" multiple="yes">
This tells PHP to treat $var as an array and each assignment of a value to var[] adds an item to the array. The first item becomes $var[0], the next $var[1], etc. The count() function can be used to determine how many options were selected, and the sort() function can be used to sort the option array if necessary.

Note that if you are using JavaScript the [] on the element name might cause you problems when you try to refer to the element by name. Use it's numerical form element ID instead, or enclose the variable name in single quotes and use that as the index to the elements array, for example:

variable = documents.forms[0].elements['var[]'];
      

How can I pass a variable from Javascript to PHP?

Since Javascript is (usually) a client-side technology, and PHP is (usually) a server-side technology, and since HTTP is a "stateless" protocol, the two languages cannot directly share variables.

It is, however, possible to pass variables between the two. One way of accomplishing this is to generate Javascript code with PHP, and have the browser refresh itself, passing specific variables back to the PHP script. The example below shows precisely how to do this -- it allows PHP code to capture screen height and width, something that is normally only possible on the client side.

Example #4 Generating Javascript with PHP

<?php
if (isset($_GET['width']) AND isset($_GET['height'])) {
  
// output the geometry variables
  
echo "Screen width is: "$_GET['width'] ."<br />\n";
  echo 
"Screen height is: "$_GET['height'] ."<br />\n";
} else {
  
// pass the geometry variables
  // (preserve the original query string
  //   -- post variables will need to handled differently)

  
echo "<script language='javascript'>\n";
  echo 
"  location.href=\"${_SERVER['SCRIPT_NAME']}?${_SERVER['QUERY_STRING']}"
            
"&width=\" + screen.width + \"&height=\" + screen.height;\n";
  echo 
"</script>\n";
  exit();
}
?>



PHP and COM> <Password Hashing
[edit] Last updated: Fri, 22 Jul 2011
 
add a note add a note User Contributed Notes PHP and HTML
Andreas R. 01-May-2007 12:14
Actually Example 56.1 doesn't conform to what is stated in the text above it, namely:
* HTML interpretation. In order to specify a random string, you must include it in double quotes, and htmlspecialchars() the whole value.
In the example code single quotes are used instead of double quotes:
<?php
    
echo "<input type='hidden' value='" . htmlspecialchars($data) . "' />\n";
 
?>
which should be instead:
<?php
    
echo "<input type='hidden' value=\"" . htmlspecialchars($data) . "\" />\n";
 
?>
If single quotes are used, they should be escaped too using ENT_QUOTES quote style for htmlspecialchars.
francesco 07-Nov-2006 02:41
Another way to pass variables from JavaScript to PHP.

<script type="text/javascript" language="JavaScript">
<!--
function getScreenResolution()
{
    return document.form.ScreenResolution.value = screen.width + "x" + screen.height;
}
//-->
</script>
<form name="form" action="screen.php?show=ok" method="post" >
<input name="ScreenResolution" type="text" size="20" maxlength="9" />
<input name="show" type="submit" value="Submit" onclick="getScreenResolution()" />
</form>
<?php
   
echo $_POST['ScreenResolution'];
?>
tchibolecafe at freemail dot hu 12-Aug-2006 11:34
Notes on question "1. What encoding/decoding do I need when I pass a value through a
form/URL?"

Doing an htmlspecialchars() when echoing a string as an HTML attribute value is not enough to make the string safe if you have accented (non-ASCII) characters in it. See http://www.w3.org/TR/REC-html40/appendix/notes.html#non-ascii-chars

The referred document recommends the following method to be used:

<?php
 
function fs_attr($path){
   
$retval='';
    for(
$i=0;$i<strlen($path);$i++){
     
$c=$path{$i};
      if(
ord($c)<128){
       
$retval.=$c;
      }else{
       
$retval.=urlencode(utf8_encode($c));
      }
    }
    return
htmlspecialchars($retval);
  }

 
$img_path='éöüä.jpg';
  echo
'<img src="'.fs_attr($img_path).'">';
?>

However, using utf8 encoding for path names is among others supported by Windows NT, above method fails when running for example on an Apache server on Linux.

A more fail safe way:

<?php
       
function fs_attr($path){
               
$retval='';
                for(
$i=0;$i<strlen($path);$i++){
                       
$c=$path{$i};
                        if(
ord($c)<128){
                               
$retval.=$c;
                        }else{
                                if(
PHP_OS==='WINNT')
                                       
$retval.=urlencode(utf8_encode($c));
                                else
                                       
$retval.=urlencode($c);
                        }
                }

                return
htmlspecialchars($retval);
        }
?>

There may be operating systems that want utf8 encoding, other than WINNT. Even this latter one won't work on those systems. I don't know about any possibility to determine immediately which encoding to be used on the file system of the server...
dot dot dot NO php SPAM at NO willfris dot nl SPAM dot dot dot 12-Jul-2006 10:19
@Torsten{
In http://www.w3.org/TR/xhtml1/#C_8 it says:
"Unfortunately, this constraint cannot be expressed in the XHTML 1.0 DTDs."
}

http://www.w3.org/TR/xhtml1/#C_8 also says: "When defining fragment identifiers to be backward-compatible, only strings matching the pattern [A-Za-z][A-Za-z0-9:_.-]* should be used."
I'll come back to this.

Since it's all about fragment identifiers, I can't see why using an array like arrayname[] would be used. I think arrayname[name] should be used this way the fragment identifiers stay unique.
Since [ and ] are not allowed, why not use something what is allowed and use str_replace?
example:   :_. = [ & ._: = ]   so: name="arrayname:_.name._:" OR name="arrayname:_.0._:" and offcourse also add the id attribute then for backward compatibility.
Torsten 22-Feb-2006 10:30
Section C.8 of the XHTML spec's compatability guidelines apply to the use of the name attribute as a fragment identifier.  If you check the DTD you'll find that the 'name' attribute is still defined as CDATA for form elements.
jetboy 30-Dec-2005 03:06
While previous notes stating that square brackets in the name attribute are valid in HTML 4 are correct, according to this:

http://www.w3.org/TR/xhtml1/#C_8

the type of the name attribute has been changed in XHTML 1.0, meaning that square brackets in XHTML's name attribute are not valid.

Regardless, at the time of writing, the W3C's validator doesn't pick this up on a XHTML document.
FatalError 29-Dec-2005 10:29
Actually, you can pass variables between JavaScript and PHP without even refreshing the page. To do this, you have to use AJAX, which is what dmsuperman at comcast dot net was showing in that example.
tms at infamous dot net 23-Nov-2005 02:23
Regarding drane's claim that square brackets ([]) in form input elements (as PHP uses for arrays in forms) are invalid HTML: the NAME attribute of an input element is CDATA, not NAME or ID.

Square brackets are allowed in CDATA, no problem.

(Link is mangled because it's too long:

http://www.w3.org/TR/1999/REC-html401-19991224/ interact/forms.html#h-17.4
rybasso 06-Oct-2005 09:19
If U wish to build POST request depend on form which contains select-multiple use the following js code:

var id = theForm.elements[e].id;

if (theForm.elements[e].type=='select-multiple') {
                for (f=0;f<theForm.elements[e].length;f++) {
                    if(theForm.elements[e].options[f].selected==true)
                         qs+= id+'['+f+']='+escape(theForm.elements[e].options[f].value);
                         qs+=(qs=='')?'':'&';   
                }
            }
dmsuperman at comcast dot net 10-Sep-2005 04:05
Here's a great way to pass JavaScript to PHP without even leaving the page:

<script type="text/javascript">
<!--

function xmlreq(){
  if(window.XMLHttpRequest){
    req = new XMLHttpRequest();
  }else if(window.ActiveXObject){
    req = new ActiveXObject("Microsoft.XMLHTTP");
  }
  return(req);
}
function sendPhp(url){
  var req = xmlreq();
  req.onreadystatechange = stateHandler;
  req.open("GET", url, true);
  req.send(null);
}

sendPhp("updatedatabase.php?username=blah&displayname=whatever");
//-->
</script>
fuchs at michaelfuchs dot org 09-Aug-2005 07:54
Here's a new one, which might cause problems for people:

To make my multiple select box contents accessible to both PHP and JavaScript (using getElementById()), I was using both name and id attributes - and naming them the same, for consistency:

<select multiple="multiple" id="bob[]" name="bob[]">

However, I've discovered that - for reasons unknown - using the brackets in the id causes only a single value (rather than multiple values) to get returned to the $_POST['bob'] array. What you want is:

<select multiple="multiple" id="bob" name="bob[]">

Hope this saves some time/frustration.
fib at affordit dot fr 13-Jul-2005 02:26
I was working on a small interface for a client and he wanted a template to be generated dynamically. The issue came up when I had to retrieve the values for an array of text variables. I couldn't find any tutorial to help me out so after a few investigations this is how I made it work:
 
<?php

  $line_class
=array();
 
$line_item=array();
 
    for (
$i=$rows_number;$i>0;$i--)
      {
      
$line_class[$i]=$_POST['line_class'.$i.''];
      
$line_item[$i]=$_POST['line_item'.$i.''];
      }

?>

 Hope this helps someone ... at least they will do the job sooner than I did :D.
levinb at cs dot rpi dot edu 17-Jun-2005 04:17
Well, I was working on this one project, on the assumption that I could get the values of all elements with the same name from an appropriately named array.  Well, I was *very* disappointed when I couldn't, so I made it so I did anyway.

The following script should convert the raw post data to a $_POST variable, with form data from SELECT elements and their ilk being transformed into an array.  It's heavily unoptimized, and I probably missed something, but it's relatively easy to read.  I welcome corrections.

<?php

if ($_POST) {
       
$postdata = file_get_contents('php://input');
       
       
$uglybugger = '/(?<=&)([^&=]+)(?:=([^&]*))/';
       
$matches = array();

       
preg_match_all($uglybugger, $postdata, $matches);

       
$_POST = array();

       
$match_count = count($matches[0]);
        for (
$i = 0; $i < $match_count; $i++) {
                if (!isset(
$_POST[$matches[1][$i]])) {
                       
$_POST[$matches[1][$i]] = array();
                }
               
$_POST[$matches[1][$i]][] = $matches[2][$i];
        }
       
$match_count = count($_POST);
        for (
$i = 0; $i < $match_count; $i++) {
                if (
count($_POST[$i]) == 1) {
                       
$_POST[$i] = $_POST[$i][0];
                }
        }
}

?>
noah at noah dot org 10-May-2005 05:10
In your action, "random_picker_action.php"
shouldn't you initialize $picks? The code didn't work
for me until I added the line:
    $picks = $_REQUEST['picks'];

Here is the full random_picker_action.php

Yours,
Noah

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
   <title>How to Pass an Array from Javascript to PHP: Action Page</title>
  <!-- File: random_picker_action.php -->
</head>
<body>
<p>
<h3>How to Pass an Array from Javascript to PHP: Action Page</h3>
<?php
  $picks
= $_REQUEST['picks'];
 
$picks = urldecode(stripslashes($picks));
  echo
"<b>JavaScript said: " . $picks . "</b><p>";
 
$picks = unserialize($picks);
  if(
sizeof($picks) > 0)
  {
  
reset($picks);
   echo
"You picked the following items:<p>";
   while(
$item = each($picks))
     echo 
$item['value'] . " off, " . str_replace("_", " ", $item['key']) . "<br>";
  }
  else
   echo
"You did not pick any items<p>";
?>
</body>
</html>
richard dot prangnell at ntlworld dot com 27-Feb-2005 05:09
Further to my note posted on  26-Feb-2005 at 04:44, I have refined the JavaScript function "send_picks()" to make it more robust and universal. The original version was designed to handle string keys and +ve integer key values only; fine for the original purpose of handling random picks for a shopping cart application but it produced a mal-formed array if any -ve or non-integer key values were submitted. The new version treats both keys and key values as strings, irrespective of the data type; and we all know just how easy it is to manipulate numeric strings as numbers in PHP:-). Key values can now be anything you like; including:
"5"
"2 dozen"
"A gross"
"12.5"
"blue"
and so forth. Here's the updated code:

    <script type="text/javascript">
      function send_picks()
      {
        form1.picks.value="";
        var e, picked = 0;
        for (var i = 0 ; i < form1.elements.length - 2; i++)
        {
          e = form1.elements[i];
          if(e.value != "0" && e.value.length > 0)
          {
            e = form1.elements[i]
            picked++;
                form1.picks.value = form1.picks.value + "s:"
              + e.name.length + ":\"" + e.name + "\";s:"
              + e.value.length + ":\"" + e.value + "\";";
          }
        }
        form1.picks.value = "a:" + picked + ":{" + form1.picks.value + "}";
      }
    </script>

Note the line:
        for (var i = 0 ; i < form1.elements.length - 2; i++)
The  "-2" term is to let the function skip the last 2 elements in the form, a "hidden" input and the "submit" button. No doubt different form layouts will need a different value here.
An incidental bonus is that getting JavaScript to process a floating point input as a string rather than a number avoids the usual rounding errors that tend to turn an input such as "1.2" into a number beginning 1.199999... with about 30 places of decimals - yes, its JavaScript rather than PHP that is responsible for this kind of behaviour.
richard dot prangnell at ntlworld dot com 26-Feb-2005 04:44
The following HTML form page and PHP action page illustrate an elegant and powerful client side JavaScript to server side PHP data transfer technique perfectly matched to PHP's associative array feature. Browse to the form page and select some items by entering an INTEGER > 1 then click on Submit (Don't put strings or reals in the input fields - error trapping has been stripped out for brevity). Try selecting one, some, all or none of the items, changing the names of the form input variables (and the associated labels, for clarity!) or adding to the number of items "on offer". At no point do you need to alter either the JavaScript function or the action page in any way - just be aware that extra coding and error trapping is required - especially where the key values in the application could be something other than integers:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
    <title>How to Pass an Array from Javascript to PHP: Form Page</title>
  <!-- File: random_picker.php -->
    <script type="text/javascript">
      function send_picks()
      {
        form1.picks.value="";
        var picked = 0;
        for (var i = 0 ; i < form1.elements.length; i++)
        {
          if(form1.elements[i].value > 0)
          {
            e = form1.elements[i]
            picked++;
                form1.picks.value = form1.picks.value + "s:" + e.name.length + ":\""
            + e.name + "\";i:" + e.value + ";";

          }
        }
        form1.picks.value = "a:" + picked + ":{" + form1.picks.value + "}";
      }
    </script>
</head>
<body>
<p>
<h3 align="center">How to Pass an Array from Javascript to PHP: Form Page</h3>
<form name="form1" action="random_picker_action.php" method="post"
  onsubmit="JavaScript:send_picks()">
<table align="center" border="1" cellpadding="5" cellspacing="0">
  <tr><td>Item 13</td>
  <td><input type="text" name="item_13" value="0" size="4"></td>
  </tr>
  <tr><td>Part number 2</td>
  <td><input type="text" name="Part_number_2" value="0" size="4"></td>
  </tr>
  <tr><td>Drawing ref 327</td>
  <td><input type="text" name="Drawing_ref_327" value="0" size="4"></td>
  </tr>
  <tr><td>Organic Carrots</td>
  <td><input type="text" name="Organic_carrots" value="0" size="4"></td>
  </tr>
  <tr><td colspan="2" align="center">
      <input type="submit" value="Submit Picks">
      <input type="hidden" name="picks" value=""></td>
  </tr>
</table>
</form>
</body>
</html>

The action page for the above form page is listed below. Notice the really ingenious feature; the form variable is simply unserialized  to turn it into a fully functional PHP array! The action page doesn't need to know anything about "expected" variable names because everything PHP needs to know is right inside the array. Note also that for maximum efficiency only "picked" item data is sent. If no items at all are picked, a perfectly formed empty array is sent:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
    <title>How to Pass an Array from Javascript to PHP: Action Page</title>
  <!-- File: random_picker_action.php -->
</head>
<body>
<p>
<h3>How to Pass an Array from Javascript to PHP: Action Page</h3>
<?php
  $picks
= urldecode(stripslashes($picks));
  echo
"<b>JavaScript said: " . $picks . "</b><p>";
 
$picks = unserialize($picks);
  if(
sizeof($picks) > 0)
  {
   
reset($picks);
    echo
"You picked the following items:<p>";
    while(
$item = each($picks))
      echo 
$item['value'] . " off, " . str_replace("_", " ", $item['key']) . "<br>";
  }
  else
    echo
"You did not pick any items<p>";
?>
</body>
</html>

I hope you find this technique useful - let me know what you think - I can already hear the jaws of Java Jocks dropping!
alberto dot delatorre at gmail dot com 15-Jan-2005 07:41
Other way to make a form with array fields, and use JavaScript features on them, is use both name and id attributes on the field as:

<input type="text" name="myfield[]" id="myfield1"/>
<input type="text" name="myfield[]" id="myfield2"/>
<script language="JavaScript">
document.getElementById("myfield1");
document.getElementById("myfield2");
</script>

This is an easy way to do it. To number the fields, do a simple for structure and you have done.
dreptack at op dot pl 02-Jan-2005 08:37
I needed to post html form through image input element. But my problem was I had to use multiple image-buttons, each one for a single row of form table. Pressing the button was mention to tell script to delete this row from table and also (in the same request) save other data from the form table.
I wrote simple test-script to see what variable I should check for in a script:

I have a html document:

<form action="test.php" method="post">
<input type="image" name="varscalar" src="/images/no.gif" />
<input type="image" name="vararray[12]" src="/images/no.gif" />
</form>

And a php script:
<?php
 
if ($_POST) {
    echo
"post: <pre>"; print_r($_POST); echo '</pre>';
  }
?>

What I've discovered suprised me a lot!

After hitting on varscalar:

post:
Array
(
    [varscalar_x] => 6
    [varscalar_y] => 7
)

After hitting on upper right corner of vararray:

post:
Array
(
    [vararray] => Array
        (
            [12] => 2
        )

)

This mean when clicking on image-type input element, which name is an array, only y-part of a value is remembered.

The result is the same on: php 4.1.2 on Win98se, php 4.3.9-1 on linux
seec77 at zahav dot net dot il 22-Dec-2004 11:35
Another unfortunate result of appending "[]" to input field names to pass form data in arrays to PHP, is that people will be able to detect you are running PHP. You can tell by the whole documentation section on hiding PHP, that some people might not want the public to know their site is generated with PHP (usually for security reasons), but the "[]" will blow your cover.
So beware! If you are trying to hide PHP, you will have to stay away from passing form data as arrays!
Karen 05-Aug-2004 12:38
I am using code I got from SitePoint that uses stripslashes because of magic quotes...I finally figured out that it kept my html form select multiple field from working correctly even though I was using name="arrName[]" as the field name -- I was only getting the word array as the value, and all the things I tried there was nothing else there. The stripslashes was part of an included include file, so it took me hours to debug.  Hopefully this will help keep others from wasting time.
Jim Granger 19-Jun-2004 05:11
Kenn White wrote:

So for XHTML strict, the bottom line:
 1. form, use id, not name
 2. input, use id if you can, but if you need to use bracketed notation (for example, passing PHP arrays), i.e., foo[], you *MUST* use name for XHTML strict validation.

I don't think they are going to deprecate name entirely. For one thing, to be of any use, radio boxes and occasionally checkboxes must have the same identifying mark, in this case a name. By the rules of the DTD, id's MUST be unique. In that respect, it is probably better to not use id in input elements at all.

Of course, it's a good idea to use ids as sparingly as possible.
ppmm at wuxinan dot net 13-Jun-2004 11:11
3. How do I create arrays in a HTML <form>?

The feature is nice in the sense of simplifying programming. However, this does have side-effect. Look at this URL below:

http://www.php.net/source.php?url[]=/index.php

As a common viewpoint, exposing the absolute filesystem path in the webpage is always a bad thing. I reported this problem at bugs.php.net a few days before and I get a response saying "it's up to programmers". I think it's fair, however, webmaster should really learn to check the variables at the beginning of the script. In the above case, the PHP script should at least check like this:

if (!is_string(url)) die("with some error message");

As what I experienced, many PHP-based websites have this problem. I would think a perfect solution is that PHP does not do this automatic parsing, and when a PHP script expects an array to be posted, they would do something like

parse_http_array($_GET, "url");

only after this point, $_GET['url']) exists. Before this statement, only $_GET['url[]'] is available. Well, I am kind of too demanding I guess, but what I really intended to say is that webmaster should know this problem.
vlad at vkelman dot com 05-Jun-2004 02:04
"4.  How do I get all the results from a select multiple HTML tag?"

I think that behavior of PHP which forces to use [] after a name of 'select' control with multiple attribute specified is very unfortunate. I understand it comes from old times when registerglobals = on was commonly used. But it creates incompatibility between PHP and ASP or other server-side scripting languages. The same HTML page with 'select' control cannot post to PHP and ASP server pages, because ASP does not require [] and automatically recognize when arrays are posted.
Kenn White kennwhite dot nospam at hotmail dot com 13-Mar-2004 04:18
Concerning XHTML Strict and array notation in forms, hopefully the information below will be useful:

If I have a form, name="f", and, say, an input text box, name="user_data[Password]", then in Javascript, to reference it I would do something like:
   
var foo = f['user_data[Password]'].value;

Now, say that in making the switch to XHTML strict, I decide to fully embrace standards compliance, and change my form to id="f", and the input text box to id="user_data[Password]"

Because these have id instead of name, I discover, that all my javascript validation routines just broke.  It seems that I have to now change all my js code to something like:

document.getElementById( 'user_data[Password]' ).focus();

I test this on all the major modern browsers, and it works well.  I'm thinking, Great!  Until I try to validate said page.  It turns out that the bracket characters are invalid in id attributes.  Ack!  So I read this thread:

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=
UTF-8&th=78dea36fd65d9bbe&seekm=
pqx99.19%24006.13377%40news.ca.inter.net#link11
(link needs to be spliced, sorry)

What does this mean, I start asking myself?  Do I have to abandon my goal to migrate to XHTML strict?  Transitional seems so unsatisfying.  And why bother with a technique that seems to work on most browsers, if it's broken.  Alas, there is hope.

But then I read http://www.w3.org/TR/xhtml1/#h-4.10 carefully.  It says "name" is deprecated as a form attribute, but *NOT* specifically as an attribute in form *elements*.  It seems my solution is to use "id" for the form itself, but I can legally use "name" for the individual form components, such as select and text input boxes.  I get the impression that "name" as an attribute is eventually going away completely, but in extensive testing using the W3C validator, it passes "name" on form components, as long as "id" (or, strangely, nothing) is used to denote the form itself.

So for XHTML strict, the bottom line:
 1. form, use id, not name
 2. input, use id if you can, but if you need to use bracketed notation (for example, passing PHP arrays), i.e., foo[], you *MUST* use name for XHTML strict validation.
 
-kenn

kennwhite.nospam@hotmail.com
davis at risingtiger dot net 09-Jan-2004 08:14
I thought this might be useful to fellow PHP heads like myself out there.

I recently came across a need to transfer full fledged mutli-dimensional arrays from PHP to JAVASCRIPT.

So here it is and hopefuly good things come from it.

<?php
function phparray_jscript($array, $jsarray)
{
    function
loop_through($array,$dimen,$localarray)
    {
        foreach(
$array as $key => $value)
        {
            if(
is_array($value))
            {
                echo (
$localarray.$dimen."[\"$key\"] = new Array();\n");
               
loop_through($value,($dimen."[\"".$key."\"]"),$localarray);
            }
            else
            {
                echo (
$localarray.$dimen."[\"$key\"] = \"$value\";\n");
            }
        }
    }

    echo
"<script language=\"Javascript1.1\">\n";
    echo
"var $jsarray = new Array();\n";
   
loop_through($array,"",$jsarray);
    echo
"</script>";
}
?>
email at njschedules dot com 19-Oct-2003 04:13
If you try to include an XHTML document in a PHP document, you may be including this:

<?xml version="1.0" encoding="iso-8859-1"?>

which would, of course, be read as PHP code. To avoid this problem, use:

<?php echo "<?xml version=\"1.0\" encoding=\"iso-8859-1\"?>"; ?>

Hope I can save you from those nasty warning messages :)
03-Oct-2003 10:25
Responding to the suggestion for using this line:

<form onSubmit="selection.name=selection.name + '[]'">

This did not work for me.  I had to make a function makeArray:

function makeArray(selectBox)
{
selectBox.name=selectBox.name + "[]";
}

Then, in the submit button, add this:

onClick='makeArray(this.form.selection)'

I couldn't get anything else to work.

--Rafi
jasonpb at bellsouth dot net 30-Sep-2003 06:29
Another good way for passing javascript to php without having to have a page reload is to use an img tag.

(example)
Add this where you want to collect the vars from
This can also be a .html page
<script language="javascript">
<!--//
// Define variables
if (navigator.appname != 'Netscape') {color= "color="+screen.colorDepth+"&";}
else {color = "color="+screen.pixelDepth+"&";}
avail = "avail="+screen.availwidth+"x"+screen.availheight+"&";
res = "res="+screen.width+"x"+screen.height;
isize = '" width="1" height="1" border="0"';
// Generate img tag
img = '<img name="img"
src="javascript.php?'+color+avail+res+isize+'">';
//Print it to browser
document.write(img);
//-->
</script>

Now you have the javascript vars passed along to the javascript.php page, all thats left is to add a couple lines of php code to gather the info up.

(example)
<?
// Get the vars from the javascript
$res = $_GET['res'];
$avail_res = $_GET['avail'];
$color_depth = $_GET['color'];
// Do something with the info
echo "You Screen's Resolution is $res, Your Available Screen Resolution is $avail_res, and the Color Depth on your screen is $color_depth.";
?>
Thats it!!
Hope it may help someone!
martellare at hotmail dot com 15-Mar-2003 08:28
I do not think you are right about not being able to specify something for the value attribute, but I can see where you would have thought it would fail:

A fair warning about testing to see if a variable exists...
when it comes to strings, the values '' and '0' are interpreted as false when tested this way...

<?php
if ($string) { ... }  //false for $string == '' || $string == '0'
?>

The best practice for testing to see if you received a variable from the form (which in the case of a checkbox, only happens when it is checked) is to test using this...

<?php
if ( isSet($string) ) { ... } //true if and only if the variable is set
?>

The function tests to see if the variable has been set, regardless of its contents.

By the way, if anyone's curious, when you do make a checkbox without specifying the value attribute, the value sent from the form for that checkbox becomes 'on'.  (That's for HTML in general, not PHP-specific).
martellare at hotmail dot com 26-Nov-2002 07:25
A JavaScript Note: Using element indexes to reference form elements can cause problems when you want to add new elements to your form; it can shift the indexes of the elements that are already there.

For example, You've got an array of checkboxes that exist at the beginning of a form:
===================

<FORM>
    <INPUT type="checkbox" name="fruits[]" value="apple">apple
    <INPUT type="checkbox" name="fruits[]" value="orange">orange
    <INPUT type="checkbox" name="fruits[]" value="banana">banana
</FORM>

===================
... These elements could be referenced in JavaScript like so:
===================

<SCRIPT language="JavaScript" type="text/javascript">
<!--
    var index = 0; //could be 1 or 2 as well
    alert(document.forms[0].elements[index]);
//-->
</SCRIPT>

===================
However, if you added a new textbox before these elements, the checkboxes indexes become 1 - 3 instead of 0 - 2;  That can mess up what ever code you create depending on those indexes.

Instead, try referencing your html arrays in JavaScript this way.  I know it works in Netscape 4 & IE 6, I hope it to some extent is universal...
===================

<SCRIPT language="JavaScript" type="text/javascript">
<!--
    var message = "";
    for (var i = 0; i < document.forms[0].elements['fruits[]'].length; i++)
    {
        message += "events[" + i + "]: " + document.forms[0].elements['fruits[]'][i].value + "\n";
    }
    alert(message);
//-->
</SCRIPT>

===================
karatidt at web dot de 17-Nov-2002 08:57
this code selects all elements with javascript
and hands them over to an array in php *sorry my english is not good*

javascript:

<script language="JavaScript">
<!--
function SelectAll(combo)
 {
   for (var i=0;i<combo.options.length;i++)
    {
      combo.options[i].selected=true;
    }
 }
//-->
</script>

html code:
<form name="form" action="<?php echo $_SERVER["PHP_SELF"]; ?>" method="post">
<select name="auswahl[]" size="10" multiple>
<option value="bill@ms.com">Bill Gates</option>
<option value="bill@unemployed.com">Bill Clinton</option>
<option value="bart@brat.com">Bart Simpson</option>
<option value="oj@free.com">OJ Simpson</option>
<option value="j@nbc.com">Jay Leno</option>
</select>

<input type="submit" name="submit1"  value="OK" onclick="SelectAll(document.form.elements['auswahl[]'])">
</form>

php code:

$auswahl = $_POST["auswahl"];
       
foreach ($auswahl as $value)
    {
        echo $value."<br>";
    }
bas at cipherware dot nospam dot com 17-Oct-2002 04:52
Ad 3. "How do I create arrays in a HTML <form>?":

You may have problems to access form elements, which have [] in their name, from JavaScript. The following syntax works in IE and Mozilla (Netscape).

index = 0;
theForm = document.forms[0];
theTextField = theForm['elementName[]'][index];
hjncom at hjncom dot net 25-May-2002 10:30
I think '[' and ']' are valid characters for name attributes.

http://www.w3.org/TR/html401/interact/forms.html#h-17.4
-> InputType of 'name' attribute is 'CDATA'(not 'NAME' type)

http://www.w3.org/TR/html401/types.html#h-6.2
-> about CDATA('name' attribute is not 'NAME' type!)
...CDATA is a sequence of characters from the document character set and may include character entities...

http://www.w3.org/TR/html401/sgml/entities.html
--> about character entity references in HTML 4
([ - &#91, ] - &#93)

 
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