一、load事件
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<!DOCTYPE HTML><html><head> <meta charset="utf-8">
<title>img - load event</title>
</head><body> <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
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<!DOCTYPE HTML><html><head> <meta charset="utf-8">
<title>img - readystatechange event</title>
</head><body> <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> |
readyState为complete和loaded则表明图片已经加载完毕。测试IE6-IE10支持该事件，其它浏览器不支持。
三、img的complete属性
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<!DOCTYPE HTML><html><head> <meta charset="utf-8">
<title>img - complete attribute</title>
</head><body> <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。
<!DOCTYPE HTML>
<html><head> <meta charset="utf-8">
<title>img - complete attribute</title>
</head><body> <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>