<HEAD>
<META http-equiv="Content-Type" content="text/html; charset=GB2312">
</HEAD>
<form id="Form1" οnsubmit="return check()" method="post" encType="multipart/form-data"
<INPUT id="File1" style="WIDTH: 496px; HEIGHT: 20px" type="file" accept="image/*" size="20000"
name="File1" runat="server">
</form>
<script language="javascript" type="text/javascript">
function check()
{
var aa=document.Form1.File1.value.toLowerCase().split('.');//以“.”分隔上傳文件字符串
if(document.Form1.File1.value=="")
{//無圖片上傳
return true;
}
else
{
if(aa[aa.length-1]=='gif'||aa[aa.length-1]=='jpg'||aa[aa.length-1]=='bmp')//判斷圖片格式
{return true;}
else
{alert('對不起，你選擇的圖片格式不對/n圖片格式應爲*.jpg、*.gif、*.bmp');
return false;}
}
}
//當然也可以[判斷文件大小
</script>