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I obtained a value in PHP and wanna use it in javascript.

Is there any way to do so ??

Here is the code i am using which is not working

$var = "abc"; 

document.getElementById(<?php echo $act;?>).class="active";

I am using echo $var inside the getElementById method..

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2  
possible duplicate of Is it possible to pass a php variable inside javascript? and many many others – deceze Jul 24 '11 at 5:58

4 Answers

up vote 6 down vote accepted

Your code should look like this:

<script type="text/javascript">
    document.getElementById("<?php echo($var); ?>").className = "active";
</script>

Please note that to change the "class" in JavaScript, you have to access it with the "className" property, not "class".

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You could probably make it a little easier (and safer) by using json_encode(), e.g. document.getElementById(<?php echo json_encode($var); ?>).className = "active";. – El Yobo Jul 24 '11 at 6:18
up vote 1 down vote

This should work, if your PHP code (in the Javascript one) is placed in a .php file -- which are executed by the PHP interpreted, while .js ones are not.


Note that you should place quotes arround the id you pass to getElementById :

document.getElementById('<?php echo $act;?>').class="active";

And, of course, your JS code must be placed between <script> tags :

<script type="text/javavascript">
    document.getElementById('<?php echo $act;?>').class="active";
</script>
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1  
It should be "className" rather than "class", btw. – Jordan Jul 24 '11 at 6:03
Oh, didn't notice that ; here's an upvote for your answer, which is then better than mine, on that part :-) – Pascal MARTIN Jul 24 '11 at 6:13
up vote 1 down vote

That is the correct usage except for one thing: document.getElementById() expects a string, but when you echo $act you get abc without quotes. So you need to do:

document.getElementById("<?php echo $act;?>").className ="active";
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up vote 1 down vote

Yes, that should work. But note that PHP is a pre-processor, so your code would end up as:

document.getElementById(abc).class="active";

instead of:

document.getElementById("abc").class="active";

note the missing quote. anyway, I assume you use the name correctly, in your post you declare $var but echo $act.

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1  
It should be "className" rather than "class", btw. – Jordan Jul 24 '11 at 6:03

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