JS获取URL参数方法

//js get url param
var getParam = function(name){
var search = document.location.search;
var pattern = new RegExp("[?&]"+name+"\=([^&]+)", "g");
var matcher = pattern.exec(search);
var items = null;
if(null != matcher){
try{
items = decodeURIComponent(decodeURIComponent(matcher[1]));
}catch(e){
try{
items = decodeURIComponent(matcher[1]);
}catch(e){
items = matcher[1];
}
}
}
return items;
};

getParam('PId');