1.添加时间监听:
Chrom中:
addEventListener的使用方式:
target.addEventListener(type, listener, useCapture);
target: 文档节点、document、window 或 XMLHttpRequest。
type: 字符串,事件名称,不含"on",比如"click"、"mouseover"、"keydown"等。
listener :实现了 EventListener 接口或者是 JavaScript 中的函数。
useCapture :是否使用捕捉,看了后面的事件流一节后就明白了,一般用 false 。
事件触发时,会将一个 Event 对象传递给事件处理程序,比如: document.getElementById("testText").addEventListener("keydown", function (event) { alert(event.keyCode); }, false);
IE中:
target.attachEvent(type, listener);
target: 文档节点、document、window 或 XMLHttpRequest。
type: 字符串,事件名称,含"on",比如"onclick"、"onmouseover"、"onkeydown"等。
listener :实现了 EventListener 接口或者是 JavaScript 中的函数。 例如:document.getElementById("txt").attachEvent("onclick",function(event){alert(event.keyCode);});
两者使用的原理:可对执行的优先级不一样,下面实例讲解如下:
a.attachEvent方法,为某一事件附加其它的处理事件。(不支持Chrome系列)
document.getElementById("btn").onclick = method1; document.getElementById("btn").onclick = method2; document.getElementById("btn").onclick = method3;//如果这样写,那么将会只有medhot3被执行
如果写成这样:
var btn1Obj = document.getElementById("btn1"); //object.attachEvent(event,function); btn1Obj.attachEvent("onclick",method1); btn1Obj.attachEvent("onclick",method2); btn1Obj.attachEvent("onclick",method3);//执行顺序为method3->method2->method1
b.addEventListener方法 用于 Chrome系列
如果是Chrome系列,并不支持该方法,需要用到addEventListener
var btn1Obj = document.getElementById("btn1"); //element.addEventListener(type,listener,useCapture); btn1Obj.addEventListener("click",method1,false); btn1Obj.addEventListener("click",method2,false); btn1Obj.addEventListener("click",method3,false);//执行顺序为method1->method2->method3
所以要兼容Chrome和IE,要写if判断,举例:(要注意的是div必须放到js前面才行,文件编码为utf-8)
<html> <head> <meta charset="utf-8"> </head> <body> <div id="name1" style="border:1px solid red;padding:10px 10px 10px 10px;" style="border:1px solid red;padding:10px 10px 10px 10px;"> <div id="name2" style="border:1px solid green;padding:10px 10px 10px 10px;" style="border:1px solid green;padding:10px 10px 10px 10px;"> 点击 </div> </div> <div id="info"> </div> <script type="text/javascript"> var name1 = document.getElementById('name1'); //要注意 var name2 = document.getElementById('name2'); //要注意 var info = document.getElementById('info'); if (name1.attachEvent) { //对于attachEvent前面的target我们一定要保证不为空 name1.attachEvent('onclick', function() { info.innerHTML += "红色" + "<br>"; }); name2.attachEvent('onclick', function() { info.innerHTML += "绿色" + "<br>"; }); } else { name1.addEventListener('click', function() { info.innerHTML += "红色" + "<br>"; }, false); name2.addEventListener('click', function() { info.innerHTML += "绿色" + "<br>"; }, false); } </script> </body> </html>
那为什么会有含"on"和不含"on"的问题?
答案要从W3C的发展时间轴来看, DOM(Document Object Model)的模型可以分为两种, DOM 0 及 DOM 2. 从数字来看就可以知道DOM 0 当然是比较旧的协议, 我们直接来看DOM2 :
DOM 0&DOM1 协定 Event(Event Name) | DOM 2 Event | Description |
onblur() | blur | The element has lost focus (that is, it is not selected by the user). |
onchange() | change | The element has either changed (such as by typing into a text field) or the element has lost focus. |
onclick() | click | The mouse has been clicked on an element. |
ondblclick() | dblclick | The mouse has been double-clicked on an element. |
onfocus() | focus | The element has gotten focus. |
onkeydown() | keydown | A keyboard key has been pressed down (as opposed to released) while the element has focus. |
onkeypress() | keypress | A keyboard key has been pressed while the element has focus. |
onkeyup() | keyup | A keyboard key has been released while the element has focus. |
onload() | load | The element has loaded (document, frameset, or image). |
onmousedown() | mousedown | A mouse button has been pressed. |
onmousemove() | mousemove | The mouse has been moved. |
onmouseout() | mouseout | The mouse has been moved off of or away from an element. |
onmouseover() | mouseover | The mouse has moved over an element. |
onmouseup() | mouseup | A mouse button has been released. |
onreset() | The form element has been reset, such as when a form reset button is pressed. | |
onresize() | The window's size has been changed. | |
onselect() | The text of a form element has been selected. | |
onsubmit() | submit | The form has been submitted. |
onunload() | unload | The document or frameset has been unloaded. |
addEventListener()这个函数只支持新的DOM2 :addEventListener(event,function,capture/bubble);
参数event如上表(DOM 2 Event)所示, function是要执行的函数, capture与bubble分别是W3C制定得两种时间模式,简单来说capture就是从document的开始读到最后一行, 再执行事件, 而bubble则是先寻找指定的位置再执行事件.
capture/bubble的参数是布尔值, True表示用capture, False则是bubble.
Windows Internet Explorer对应的EventHandler, 是 attachEvent(), 格式如下:
window.attachEvent("submit",myFunction());
比较特别的是attachEvent不需要指定capture/bubble的参数, 因为在windows IE环境下都是使用Bubble的模式.这里用个例子来表现事件的用法:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title> Rollover </title> <script type="text/javascript"> function moveOver(imgObj) { if (typeof window.addEventListener != "undefined") { imgObj.addEventListener("mouseover", function() { imgObj.src = imgObj.id + "_over.png"; }, false); imgObj.addEventListener("mouseout", function() { imgObj.src = imgObj.id + "_default.png"; }, false); } else { imgObj.attachEvent("onmouseover", function() { imgObj.src = imgObj.id + "_over.png"; }); imgObj.attachEvent("onmouseout", function() { imgObj.src = imgObj.id + "_default.png"; }); } } function rollover() { var images = document.getElementsByTagName("img"); var roll = new RegExp("rollover"); var preload = []; for (var i = 0; i < images.length; i++) { if (images[i].id.match(roll)) { preload[i] = new Image(); preload[i].src = images[i].id + "_over.png"; moveOver(images[i]); } } } if (typeof window.addEventListener != "undefined") { window.addEventListener("load", rollover, false); } else { window.attachEvent("onload", rollover) } </script> </head> <body> <p> <img id="rollover_home" name="img_home" src="rollover_home_default.png" alt="Home"> </p> <p> <img id="rollover_about" name="img_about" src="rollover_about_default.png" alt="About"> </p> <p> <img id="rollover_blog" name="img_blog" src="rollover_blog_default.png" alt="Blog"> </p> <p> <img id="logo" name="img_logo" src="logo.png" alt="Braingia Logo"> </p> </body> </html>
ps:你需要图片素材下载
上述的 typeof window.addEventListener != "undefined" 程序代码可以判断使用者的浏览器是否支持AddEventListener这个事件模型, 如果不支持就使用attachEvent.
W3C 及 IE 同时支持移除指定的事件, 用途是移除设定的事件, 格式分别如下:
W3C格式:
removeEventListener(event,function,capture/bubble);
Windows IE的格式如下:
detachEvent(event,function);