一、load事件
<!DOCTYPE HTML><html> <head> <meta charset="utf-8"><title>img - load event</title></head> <body><img id="img1" src="http://pic1.win4000.com/wallpaper/f/51c3bb99a21ea.jpg"><p id="p1">loading...</p><script type="text/javascript">img1.onload = function() {p1.innerHTML = 'loaded'}</script></body></html>
测试，所有浏览器都显示出了“loaded”，说明所有浏览器都支持img的load事件。
二、readystatechange事件
<!DOCTYPE HTML><html> <head> <meta charset="utf-8"><title>img - readystatechange event</title></head> <body><img id="img1" src="http://pic1.win4000.com/wallpaper/f/51c3bb99a21ea.jpg"><p id="p1">loading...</p><script type="text/javascript">img1.onreadystatechange = function() {if(img1.readyState=="complete"||img1.readyState=="loaded"){p1.innerHTML = 'readystatechange:loaded'}}</script></body></html>
三、img的complete属性
<!DOCTYPE HTML><html> <head> <meta charset="utf-8"><title>img - complete attribute</title></head> <body><img id="img1" src="http://pic1.win4000.com/wallpaper/f/51c3bb99a21ea.jpg"><p id="p1">loading...</p><script type="text/javascript">function imgLoad(img, callback) {var timer = setInterval(function() {if (img.complete) {callback(img)clearInterval(timer)}}, 50)}imgLoad(img1, function() {p1.innerHTML('加载完毕')})</script></body></html>
轮询不断监测img的complete属性，如果为true则表明图片已经加载完毕，停止轮询。该属性所有浏览器都支持。