：js实现上传图片时 点击浏览后 就可以看到缩略图 很实用
转载网址：http://blog.sina.com.cn/s/blog_6094f04d0100o6kj.html
<!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>无标题文档</title> </head>
<SCRIPT LANGUAGE="JavaScript">
var flag=false;
function DrawImage(ImgD){
var image=new Image();
image.src=ImgD.src;
if(image.width>0 && image.height>0){
flag=true;
if(image.width>300 || image.height>200) {
ImgD.width=image.width/2;
ImgD.height=image.height/2;
ImgD.alt=image.width+"×"+image.height;
} else {
ImgD.width=image.width;
ImgD.height=image.height;
ImgD.alt=image.width+"×"+image.height;
}
}
}
function mainChange(Value){
flag=false;
document.all.mainimage.width=5;
document.all.mainimage.height=5;
document.all.mainimage.alt="";
document.all.mainimage.src=Value;
document.all.maindiv.style.display='';
}
</SCRIPT>
<TABLE border="0">
<TBODY>
<tr>
<td height="22" colspan="5">
top:<input type="file" name="up1" style="width:300" class="textbox" onChange="javascript:mainChange(this.value);">
</td>
</tr>
</TBODY>
</TABLE>
<table height="78" border="0" cellpadding="0" cellspacing="0">
<tr>
<td >
<div id="maindiv" style="display:none">
<IMG id=mainimage height=70 width=20 src="" onload="javascript:DrawImage(this);" >
</div>
</td>
</tr>
</table>
<body> </body>
</html>