Trying to save PHP $_POST variable into javascript but it does not work

Question

I am trying to save the PHP array and $_POST value in to javascript variable but it does not work.

This is how i am doing it.

<html>
 <script>
   var username = <?php echo $_POST['username']; ?>
   var password = <?php echo $_POST['password']; ?>
   //abc(username, password);
   document.write(username+' '+password);// does not work
</script>
<body>
    <form method="post">
        Username: <input type="text" name="username" /><br />
        Password: <input type="password" name="password" /><br />
        <input type="submit" value="login" />
    </form>
</body>
</html>

How can i achieve this?

If i pass a hard coded variable to JavaScript function, that works only. Let me show you how.

<script>
function func(v1, v2){
   document.write(v1+' '+v2);// does not work 
}
</script>
<?php
$a = 25;
$b = 30; 
echo '<script>func('.$a.','.$b.');</script>'

?>

What does "does not work" mean? You'll need to be more clear about the problem and what isn't working. — j08691
– j08691, Commented Nov 3, 2013 at 21:58

Guilherme Sehn · Accepted Answer · 2013-11-04 02:12:01Z

4

Supposing your variables $_POST['username'] and $_POST['password'] are foo and bar respectively, your JavaScript code is being generated probably like this:

var username = foo
var password = bar

You need to add quotes around your values to JavaScript parse them as strings too, otherwise it will think you are assigning foo and bar variables to them.

Also, you should use addslashes to escape possible "characters in your string and prevent it from breaking your JavaScript code.

var username = "<?php echo addslashes($_POST['username']); ?>"
var password = "<?php echo addslashes($_POST['password']); ?>"

edited Nov 4, 2013 at 2:12

answered Nov 3, 2013 at 21:59

Guilherme Sehn

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6 Comments

j08691 Over a year ago

Don't forget the ending semicolons.

Guilherme Sehn Over a year ago

Semicolons in JavaScript are optional.

Hunza Ali Over a year ago

Thanks @ Guilherme Sehn, it worked. It was not working without semi columns. I added the semicolon and then terminator at the end and it worked.

j08691 Over a year ago

Yes, however it's a best practice.

Amal Over a year ago

Clear and concise. +1

|

XCS · Accepted Answer · 2013-11-03 21:58:42Z

1

You need to add quotes:

var username = "<?php echo $_POST['username']; ?>"

Otherwise JavaScript will interpret $_POST[] value as an undefined variable.

answered Nov 3, 2013 at 21:58

XCS

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