JavaScript 图片上传预览成效 _JavaScript

JavaScript 图片上传预览效果
需要用到图片上传前的预览效果

找了好久......
http://www.uploadify.com/download/
http://www.cnblogs.com/boychenney/archive/2011/10/08/2203036.html
http://www.cnblogs.com/oec2003/archive/2010/01/06/1640027.html

http://www.cnblogs.com/cloudgamer/archive/2009/12/22/ImagePreview.html

http://hi.baidu.com/%B7%E7%BE%B0%D2%BB%C2%B7%C3%C0%BA%C3/blog/item/5729103b79e5c4ccd56225ab.html

浏览器的兼容是个很大的问题

以下ie8,测试通过,但是ff,chrome不行

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
<form action="" method="post" enctype="multipart/form-data" name="form1">
<input name="attach" type="file" onchange="javascript:ShowImg(this.value);" onKeyDown="javascript:return(false);" size="20">
<script language="JavaScript">
function ShowImg(src)
{
document.getElementById("imgDiv").innerHTML="图片预览：<br><img id='imgObj' onload='javascript:GetSize()' src='file:///" + src + "'>";
}
function GetSize()
{
var width,height;
var imgObj=document.getElementById("imgObj");
width=imgObj.width;
height=imgObj.height;
document.getElementById("err_msg").innerHTML="图片大小(宽×高):<font color=red>" + width + "×" + height + "</font>";
if(width>164){
imgObj.width=164;
imgObj.height=imgObj.height/(imgObj.width/164);
}
}
/*
function GetError()
{
document.getElementById("err_msg").innerHTML="图片大小(宽×高):<font color=red>NaN</font>"; 
//document.getElementById("imgDiv").innerHTML="";
//document.getElementById("err_msg").innerHTML="图片文件不存在或格式错误！"
} 
*/
</script>
<div id="imgDiv" align="center"></div>
<div id="err_msg" align="center"></div>
</form>
</body>
</html>