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I am a learning Javascript and PHP, I am trying to do this , I have stored some variables in a PHP session, i am trying to set the values present in the session as the values in the form's input field, i have used javascript for that purpose,

PHP :

<html>
<head>
    <link rel='stylesheet' type='text/css' href='http://localhost/Matrix/frameCSS.css' />
    <script lang='text/javascript' src='http://localhost/Matrix/gd.js'></script>
</head>
<body>
    <?php
        // ------- --------- -------- -------- ------
        $debug=true;
        dBug("Started Code Execution ... ");
        function dBug($text)
        {
            global $debug;
            if($debug) { echo "<p class='status'>debug : $text</p>"; }
            else { return; }
        }
        // ------ ----------- ------------ -----------
        $db = mysqli_connect("127.0.0.1","user","xyz","sample");
        if(mysqli_connect_errno())
        {
            die(mysqli_connect_error());
        }
        session_start();
        if($_SESSION['is_open']==true)
        {
            $username = $_SESSION['username'];
            dBug('retreived username > '.$username);
        }
    ?>

    <table class="content">
        <form method="POST" action="http://localhost/gen_det.php" onload="load_data()">
           <tr>
               <td>
                    Full Name : 
               </td>
               <td>
                    <input type="text" class="txtbox" id='name'/>
               </td>
           </tr>
           <tr>
               <td>
                    Age : 
               </td>
               <td>
                    <input type="text" class="txtbox" id='age' />
               </td>
           </tr>
           <tr>
                <td>
                    <p class='status' id='status'>&nbsp;</p>
                </td>
           </tr>
           <tr>
               <td colspan="2" align='center'> 
                    <input type="submit" class="btn" onclick="return validateData();" value="save" /> 
                    <input type="button" class="btn" onclick="redirect()" value="cancel" /> 
               </td>
           </tr>
        </form>
    </table>
</body>

Javascript :

function load_data()
{
 var name = document.getElementById('name');
 var age = document.getElementById('age'); 
 name.value = " <?php echo ''.$_SESSION['username']; ?> ";
 age.value = " <?php echo ''.$_SESSION['username']; ?> ";
}

This page is actually inside a iframe in another page (if that is important). When I open this page, it opens , but the values aren't filled in the text fields. What have I done wrong ?

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5
  • 1
    Is all the code (HTML/PHP/JavaScript) inside the same page? Why are you not just using the same PHP to put it in the input fields? Seems pointless to use JavaScript here. Commented Dec 23, 2013 at 16:43
  • 1
    Where is the javascript located? If it's in it's own file, the PHP won't run. Commented Dec 23, 2013 at 16:44
  • 2
    where you have defined the javascript function. is it in the same html file or in a separate js file. Commented Dec 23, 2013 at 16:44
  • @MaNKuR Seperate file " <script lang='text/javascript' src='localhost/Matrix/gd.js'></script>" Commented Dec 23, 2013 at 16:48
  • 1
    than in this case you have to pass the php variable to that function. Becasue there is no way (as per my knowledge) to send php variable directly to javascript file until its function will be called ... so in this case you have to call that method in this way <body onload="load_data('<?php echo ''.$_SESSION['username']; ?>', ' <?php echo ''.$_SESSION['username']; ?> ');"> and then you can access this in js function as params i.e function load_data(name, age){} Commented Dec 23, 2013 at 16:51

5 Answers 5

Reset to default
3

here is the method

<body onload="javascript: load_data('<?php echo $_SESSION['name']; ?>', '<?php echo $_SESSION['age']; ?>') >

and in the JS file you can define the function 

function load_data(param_name, param_age)
{
            var name = document.getElementById('name');
            var age = document.getElementById('age'); 
            name.value = param_name;
            age.value = param_age;
}
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Comments

2

Your <form> tag cannot have an onload attribute. This is simply not possible.

Try assigning the onload event to your <body> element:

<body onload="load_data();">

A better solution would be to directly register the event in the JavaScript code:

window.addEventListener("load", load_data);
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2 Comments

that works, but i got a new problem now, the php code is displayed in the textfield instead of the values
@cyberPheonix Please try Marc B's suggestion on how to rewrite the PHP with json_encode().
2

For one, you're inserting your PHP data incorrectly. You can very easily produce JS syntax errors by directly dumping arbitrary PHP values into a JS context. You should ALWAYS use json_encode() to produce valid JS text:

name.value = <?php echo json_encode($_SESSION'username']); ?>;

json encoding will take care of any quoting/escaping necessary.

You don't mention HOW this JS is getting included in your site. If it's in (say) an external .js file, then by default this file will NOT be passed through the PHP interpreter, and you'll be sending raw un-executed PHP code to the browser, where it will be seen by the JS parser and rejected as a outright syntax error. That will kill the entire script block and your JS code dies right then and there.

If it is somehow being parsed/executed by the server, then you should directly hit that JS script file with your browser and see WHAT is being output. There could be other structural problems causing JS to ignore the entire script.

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5 Comments

ya , ya the JS is external
so if it's a .js file, you'll either have to rename it to .php so the server executes any php code within (which also means changing all of your <script> tags to point at the new filename), or reconfiguring your server to treat .js files as .php.
tried using json_encode() but still displaying PHP code instead of values.
you mean I can use the same JS code file and rename it to .php ?
yes. There's no such thing as a "php script", really. There's only files which have PHP (<?php ... ?>) within them. if there's no PHP code blocks, the file's contents get sent out unchanged.
1

If you already have the value of the data within the PHP variable you can just build the required input element with the value already included

<input type="hidden" id="foo" name="foo" value="<?php echo $_SESSION['foo']; ?>"/>

When your event (click/submit) fires the target element will then contain the value

foo = document.getElementById('foo');
console.log(foo.value);
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Comments

1

well is very simple, when a web page is loaded the load order they are as follows.

HTML->CSS->JavaScript->PHP.

So if you want to get that variable in your js file, you have to do it this way...

<html>
    <head>
        <link rel='stylesheet' type='text/css' href='http://localhost/Matrix/frameCSS.css' />
        <script lang='text/javascript' src='http://localhost/Matrix/gd.js'></script>
        <script>
            function load_data()
            {
                var name = document.getElementById('name');
                var age = document.getElementById('age'); 
                name.value = "<?php echo ''.$_SESSION['username']; ?>";
                age.value = "<?php echo ''.$_SESSION['username']; ?>";
            }
        </script>
    </head>
    <body>
        ...
    </body>
</html>
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