1 var $ = function(id){ 2 var dom = document.getElementById(id); 3 return { 4 on:function(eventType,element,callback){ 5 if(document.addEventListener){ 6 dom.addEventListener(eventType,function(e){ 7 var ev = e || window.event; 8 var target = ev.target || ev.srcElement 9 if(target.tagName.toLowerCase()===element){ 10 callback.call(target,ev); 11 } 12 },false); 13 }else{ 14 //兼容IE浏览器 15 document.attachEvent("on"+eventType,function(e){ 16 var ev = e || window.event; 17 var target = ev.target || ev.srcElement 18 if(target.tagName.toLowerCase()===element){ 19 callback.call(target,ev); 20 } 21 }); 22 } 23 } 24 } 25 };