execute php code in javascript code example

Example 1: php execute javascript

<?php
 if(your condition){
     echo "<script> window.onload = function() {
     yourJavascriptFunction(param1, param2);
 }; </script>";
?>

Example 2: how to run php inside js

You can't run PHP with javascript. JavaScript is a client 
side technology (runs in the users browser) and PHP is a 
server side technology (run on the server). If you want to 
do this you have to make an ajax request to a PHP script and 
have that return the results you are looking for.