html内容：
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>无标题页</title>
<script type="text/javascript" src="js/jquery-1.6.js"></script>
<script type="text/javascript">
$(function(){
$("#file").change(function(){
$.post("handler1.ashx",{fileName:$("#file").val()},function(){
alert("上传成功！");
})
})
})
</script>
</head>
<body>
<form id="form1" runat="server" enctype="multipart/form-data">
<div>
<input type="file" id="file" name="file" />
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="btnClick" />
</div>
</form>
</body>
</html>
ashx内容：
public void ProcessRequest(HttpContext context)
{
context.Response.ContentType = "text/plain";
context.Response.Write("Hello World");
string origin_fileName = context.Request["fileName"];
string fileName = System.IO.Path.GetFileName(origin_fileName);
string rela_Path = @"~\UserUpload\"+fileName;
string abso_Path = context.Server.MapPath(rela_Path);
HttpPostedFile file = context.Request.Files["file"];
}
file 为null。。。
郁闷-------
