js中常用判斷及函數

一、從瀏覽器url中獲取到所需參數及信息；

function getQueryString(name) {
var that = this;
if(isNULL(name)){return null}  //調用isnull
var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)", "i");
var r = window.location.search.substr(1).match(reg);
var param;
 try{
 param = decodeURI(r[2]);
 }catch(e){
 return null;
 }
if (isNULL(r) == false) {
return param;
 }
return null;
}

getQueryString("name");調用函數輸入入參即可獲取url中的name值；

二、判斷爲空

function isNULL(exp){
return !!(exp == null || typeof exp == "undefined" || exp == 0 || exp == "null" || exp == [] || exp == '{}' ||                 exp == '' || exp == {});

},

三、判斷空對象

 function isEmptyObject( obj ) {
 var name;
for ( name in obj ) {
 return false;
 }
  return true;
}