JS图片另存为（转）

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<html>
<head>
<title> New Document </title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js" type="text/javascript"></script>
<script language="JavaScript">
<!--
function downLoadImage(imagePathURL){
//如果中间IFRAME不存在，则添加
if(!document.getElementById("_SAVEASIMAGE_TEMP_FRAME"))
jQuery('<iframe style="display:none;" id="_SAVEASIMAGE_TEMP_FRAME" name="_SAVEASIMAGE_TEMP_FRAME" onload="_doSaveAsImage();"
width="0" height="0" src="about:blank"></iframe>').appendTo("body");
if(document.all._SAVEASIMAGE_TEMP_FRAME.src!=imagePathURL){
//图片地址发生变化，加载图片
document.all._SAVEASIMAGE_TEMP_FRAME.src = imagePathURL;
}else{
//图片地址没有变化，直接另存为
_doSaveAsImage();
}
}
function _doSaveAsImage(){
if(document.all._SAVEASIMAGE_TEMP_FRAME.src!="about:blank")
document.frames("_SAVEASIMAGE_TEMP_FRAME").document.execCommand("SaveAs");
}
//-->
</script>
</head>
<body>
<input type="button" value="download image" onclick="downLoadImage('http://www.blogjava.net/images/blogjava_net/weiwei/46570/r_beyond1991.jpg');">
</body>
</html>