如何使用javascript值设置php变量并在外部php文件中使用该php变量

design.php file:

 <script>
    $(".colr_sldr li img").click(function(){
    var src = $(this).attr('src');
    var value=src.substring(src.lastIndexOf('/')+1);
    <?php $var = "<script>document.write('" + value + "')</script>";?>
     });
    </script>

and use this variable in index.php file:

<?php 
include('design.php');
echo $var;
?>

here while i am printing this variable it is getting zero can any one help

you can't take var like this in php..

$var = "<script>document.write('" + value + "')</script>";?>

because php is server side language ..
and javascript is client side.

For this you have to use ajax ,get and post methods

the only solution I may know is using jquery on client side an sending your variable via ajax :

script.js

$('document).ready(function(){
       var myVar="Hello";
      $.post('design.php',myVar);

});

and in design.php you have acces to your variable with $_POST design.php

<?php 
   $myVar = $_POST['myVar'];
   echo $myVar;?>

please check http://api.jquery.com/jQuery.ajax/ for more details

or http://api.jquery.com/jQuery.post/