图片上传后即时预览

<!DOCTYPE html>
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
		//设置图片上传后预览的div样式
		<style type="text/css">
			#preview, .img, img
			{
			width:200px;
			height:200px;
			}
			#preview
			{
			border:1px solid #000;
			}
		</style>
	</head>
	<body>
		<div id="preview"></div>
		<input type="file" onchange="preview(this)" />
		//图片上传和预览
		<script type="text/javascript">
			function preview(file)
			{
			var prevDiv = document.getElementById('preview');
			if (file.files && file.files[0])
			{
			var reader = new FileReader();
			reader.onload = function(evt){
			prevDiv.innerHTML = '
			<img src="' + evt.target.result + '" />
			';
			}
			reader.readAsDataURL(file.files[0]);
			}
			else
			{
			prevDiv.innerHTML = '
			<div class="img"
				style="filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale,src=\'' + file.value + '\'"></div>
			';
			}
			}
		</script>
	</body>
</html>  

代码技巧