js上传和预览图片
测试在IE8，FF12.0和谷歌chrome都能用!
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>By：DragonDean</title>
<script type="text/javascript">
//下面用于图片上传预览功能
function setImagePreview(avalue) {
var docObj=document.getElementById("doc");
var imgObjPreview=document.getElementById("preview");
if(docObj.files &&docObj.files[0])
{
//火狐下，直接设img属性
imgObjPreview.style.display = 'block';
imgObjPreview.style.width = '150px';
imgObjPreview.style.height = '180px';
//火狐7以上版本不能用上面的getAsDataURL()方式获取，需要一下方式
imgObjPreview.src = window.URL.createObjectURL(docObj.files[0]);
}
else
{
//IE下，使用滤镜
docObj.select();
var imgSrc = document.selection.createRange().text;
var localImagId = document.getElementById("localImag");
//必须设置初始大小
localImagId.style.width = "150px";
localImagId.style.height = "180px";
//图片异常的捕捉，防止用户修改后缀来伪造图片
try{
localImagId.style.filter="progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)";
localImagId.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = imgSrc;
}
catch(e)
{
alert("您上传的图片格式不正确，请重新选择!");
return false;
}
imgObjPreview.style.display = 'none';
document.selection.empty();
}
return true;
}
</script>
</head>
<body>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td height="101" align="center">
<div id="localImag">
<img id="preview" src="http://pic.cnblogs.com/face/1023040/20160923152523.png" width="150" height="180" style="display: block; width: 150px; height: 180px;">
</div>
</td>
</tr>
<tr>
<td align="center" style="padding-top:10px;">
<input type="file" name="file" id="doc" style="width:150px;" onchange="javascript:setImagePreview();">
</td>
</tr>
</tbody>
</table>
</body>
</html>
运行：
