js获取url参数值

$urlp = function(key){
    var qstring = window.location.search;
    if (!qstring) return (!key || key == '*') ? {} : null;
    qstring = qstring.replace(/%20/g, ' ');
    qstring = qstring.substr(1); // remove ?
    var param = qstring.split('&');
    var map = new Object();
    for (var i = 0, j = param.length; i < j; i++){ var pl=param[i].split('='); map[pl[0]] = pl[1]; }
    return (!key || key == '*') ? map : map[key];
};