function CheckUpload()
{
var val = $("ctl00_ContentPlaceHolder1_FileUpload1").value;
if(val == "")
{
alert("请选择上传附件。");return false;
}
var validateFormat = new Array("txt","xls","ppt","doc","jpg","gif","dxg","dxf","dwt","zip","rar","cdr","pdf");
var fileFormat = val.substring(val.lastIndexOf(".")+1).toLowerCase();
var validate = false;
for (var i = 0; i < validateFormat.length ; i++)
{
if(fileFormat == validateFormat[i])
{
validate = true; break;
}
}
if (validate == false){alert("上传文件格式非法,请重新选择!"); return false;}
}