Get parameter from querystring

gistfile1.js

function getQueryParam( param ) {
    var query = window.location.search.substring(1);
    var vars = query.split('&');
    for( var i = 0; i < vars.length; i++ ){
        var pair = vars[i].split('=');
        if( decodeURIComponent( pair[0] ) == param ){
            return decodeURIComponent(pair[1]);
        }
    }
}