js文件封装javascript在html中获取url参数

function geturlparameter(paramname) //js 获取url参数值
        {
            var returnval="";
            try{
                var paramurl=window.location.search;
                //处理长度
                if(paramurl.length>0){
                    paramurl=paramurl.substring(1,paramurl.length);
                    var paramurlarray=paramurl.split("&");
                    for(var i=0;i<paramurlarray.length;i++){
                        if(paramurlarray[i].toLowercase().indexof(paramname.toLowercase())!=-1){
                            var temp=paramurlarray[i].split("=");
                            if(temp[0].toLowercase()==paramname.toLowercase()){
                                returnval=temp[1];
                                break;
                            }
                        }
                    }
                }
            }
            catch(e){}
            return returnval;
        }