SOURCE

/**
 * 
 * 获取url中的参数值
 * @param {String} name url中对应的参数名称
 * @param {String} url url参数
 */
function getUrlParam(name, url) {
    if (!url) url = location.href;
    name = name.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
    var regexS = "[\\?&]"+name+"=([^&#]*)";
    var regex = new RegExp( regexS );
    var results = regex.exec( url );
    return results == null ? null : results[1];
}
var url="https://mp.weixin.qq.com/cgi-bin/appmsgcopyright?action=orignal&type=1&lang=zh_CN";

var action = getUrlParam("lang",url)
console.log(action);