javascript 接收 html问号后面的参数

<script>
function QueryString(item){
var sValue=location.search.match(new RegExp("[/?/&]"+item+"=([^/&]*)(/&?)","i"))
return sValue?sValue[1]:sValue
}
alert(QueryString("id"))
alert(QueryString("lp"))
alert(QueryString("DaysPrune"))
</script>