js 委托事件的实现

浏览数：12 / 时间：2015年06月09日

测试代码

  
    
    function init() {
            var d = document.getElementById("test");
            d.appendChild(createUl());
 
            console.profile("f1");
            f1();
            console.profileEnd("f1");
 
            console.profile("f2");
            f2(d);
            console.profileEnd("f2");
        }
         
        //普通方式注册事件
        function f1() {
            var ul = document.getElementById("testUl");
 
            for (var i = 0; i < ul.childNodes.length; i++) {
                ul.childNodes[i].onclick = click;
            }
        }
         
        //事件委托
        function f2(d) {
            d.onclick = function(e) {
                var e = e || window.event;
                var target = e.srcElement || e.target;
 
                if (target.tagName == "LI") {
                    alert(target.innerHTML);
                }
            }
        }
 
        function click() {
            alert("1");
        }
 
        function createUl() {
            var ul = document.createElement("UL");
            ul.id = "testUl";
            var lis = "";
             
            for (var i = 0; i < 200; i++) {
                lis += "<li>" + i + "</li>";
            }
 
            ul.innerHTML = lis;
            return ul;
        }