JS修改URL参数，并修改前页面的地址

function changeURLArg(url,arg,arg_val){

            var pattern=arg+'=([^&]*)';

            var replaceText=arg+'='+arg_val;

            if(url.match(pattern)){

                var tmp='/('+ arg+'=)([^&]*)/gi';

                tmp=url.replace(eval(tmp),replaceText);

                return tmp;

            }else{

                if(url.match('[\?]')){

                    return url+'&'+replaceText;

                }else{

                    return url+'?'+replaceText;

                }

            }

            return url+'\n'+arg+'\n'+arg_val;

        } 

var urldest=changeURLArg(window.location.href,"userid","1");

history.pushState(null,null,urldest);