<script language="Jscript">
function chksize(strFileName){
var maxsize = 100; //定义允许文件的大小，单位KB，请根据需要自行修改！
var objStream = new ActiveXObject("ADODB.Stream");
objStream.Type = 1;
objStream.Open();
objStream.LoadFromFile(strFileName);
if(Math.round(objStream.Size/1024,2)>maxsize)
{alert ("抱歉！您选择的文件为 "+Math.round(objStream.Size/1024,2)+" KB \n超过了程序"+maxsize+" KB 的限制！");
document.form1.reset();
return false;
}
}
</script>
<form name="form1" action="" method="post">
<input type="file" name="Upfile" onchange="chksize(this.value)">
</form>
