How to parse js to get the parameter value in the current url and copy it to input_Basic knowledge

  function getObject(objectId) {
    if (document.getElementById && document.getElementById(objectId)) {
        return document.getElementById(objectId);
    } else if (document.all && document.all(objectId)) {
        return document.all(objectId);
    } else if (document.layers && document.layers[objectId]) {
        return document.layers[objectId];
    } else {
        return false;
    }
}
  function get(p){
//var url=location.search;
var url= document.URL.toString();
var tmpStr=p "=";
var tmp_reg=eval("/[?&]" tmpStr "/i");
if(url.search(tmp_reg)==-1)return null;
else{
    var a=url.split(/[?&]/);
    for(var i=0;i         if(a[i].search(eval("/^" tmpStr "/i"))!=-1)return a[i].substring(tmpStr.length);
}
}
 window.onload=function (){

getObject("key").value = get("k");  
//key作为input里的name名，接收到的值就是浏览器里的k参数
//k是浏览器里的参数名
 }