php - Mimic $_GET in Javascript

You need to get the URL parameters I'd suggest using a regular expression and/or jQuery, a quick example:

$.getUrlParameters = function(name, url) {
    var theURL = url || window.location.href;
    var results = new RegExp('[\\?&]' + name + '=([^&#]*)').exec(theURL);
    if (!results) { return 0; }
    return results[1] || 0;
}

See this similar topic:
How can I get query string values in JavaScript?