passing PHP variables to JS

[da_marek]

hi!
i found on this forum posts that describe how to pass javascript variables to php but i want to pass a php variable to javascript.
how can i do that?

[Blob]

Try something like this:

<script language="javascript">

var testVar = "<?php echo $phpTestVar ?>";
document.write(testVar);
</script>

[da_marek]

hmmm i tried and tried but nothing.. it just wont work... now i realize that this is more complicated than i thought... ill try to explain my situation:

i have a php page with 'for loop' and that loop is manipulating with variable $j. with that loop i get different field names like 'filed_name1', 'field_name2', etc.
at the beginning of the page i include javascript file (<SCRIPT language=Javascript src="vbcode.php"></SCRIPT>) and this is happening BEFORE the 'for loop'. what i want is to pass $j to that javascript file because those functions in javascript file must have different numbers just like my fields (i.e. 'theform.field_name1.focus()', 'theform.field_name2.focus()', etc)
what am i doing wrong? i think that you understand my problem and that i am not complicating your life too much...

thanks in advance!

[da_marek]

cmon, somebody who knows something about javascript?!?! 🙁 im sorry for posting javascript questions here but it is related with php in a way... PLEASE?!?!

[Kame]

I don't understand what you were trying to explain...

[dinger]

If you know how many times the loop will run simply create another loop in the header to print your JS function.

Chris

[adamgeorge]

It can get a little confusing sometimes creating JavaScript from PHP because you are creating a script within a script.

But basically once you get used to the idea it's not so hard...

You understand the basic concepts and sytax structure of JavaScript? If so, you will know you create variables similarly to PHP in JavaScript.

Your php script just has to output the appropriate text to create the variable...

here's an example:

<script language="JavaScript">
   var sVariable = <? echo "\"" . $phpVariable . "\";"; ?>
</script>

Now, notice that I echoed the extra " characters to enclose the phpVariable, as the JavaScript variable I was creating is a String. You have to take extra care when generating JavaScript from php, as it is easy to get confused with which is what, and can easily end up with syntax errors.

Now, what if I knew my $phpVariable may contain " characters? It would of course break the JavaScript string. So you would have to replace all " with \" in $phpVariable so as not to enduce a JavaScript error.

Just keep things like that in mind when generating JavaScript, and you'll see it's really not all that difficult.

k, good luck man
-Adam 🙂