$_GET

$_GET for parse query string

var $_GET = (function () {
    var getParams;
    
    return function (param) {
        if ( ! getParams ) {
            getParams = decodeURIComponent(window.location.search.slice(1))
                .split('&')
                .reduce(function _reduce (a, b) {
                    b = b.split('=');
                    a[b[0]] = b[1];
                    return a;
                }, {});
        }

        return getParams[param];
    }
})();