passing value to javascript to php variable: It do not work?

Question

In this program similar_text function do not work but echo successfully print $var_1 and $var_2. What is the exact error?

<script>
var j=prompt('1st name','Name')
var l=prompt('2nd name','Name')
</script>
<?php
$var_1 = '<script>document.write(j)</script>'; 
$var_2 = '<script>document.write(l)</script>'; 
similar_text($var_1, $var_2, $percent); 
echo $var_1, $var_2;
echo $percent; 
?>

• Marc B: PHP executes on the server, Javascript executes on the client. You can NOT mix the languages like that.

Answer 1

PHP is executed first, on the server, then it gets served and then only javascript is executed on the client-side. so the variables you are using in php part are not set at that moment.

If you need to interact with a php script from javascript, you odd to use an ajax request.

Answer 2

you need close php and open again

<script>
var j=prompt('1st name','Name')
var l=prompt('2nd name','Name')
</script>
<?php
$var_1 = '<script>document.write(?>j<?php)</script>'; 
$var_2 = '<script>document.write(?>l<?php)</script>'; 
similar_text($var_1, $var_2, $percent); 
echo $var_1, $var_2;
echo $percent; 
?>

or same.