<html>
<head>
<script language="javascript">
function cha()
{
if (document.f1.te.value == "")
{
alert("請上傳文件!");
return false;
}
else
{
document.f1.submit();
}
}
</script>
</head>
<body onload="document.f1.te.value == ''">
<form name="f1" action="b.jsp" onsubmit="return cha()">
<input type="file" name="upfile" id="uf" onclick="te.value=''" onchange="te.value = uf.value">
<input type="text" name="te" id=te value="" style="visibility:'hidden'"><br>
<input type="submit" name="sub" value="確定"></body>
</form>
</html>
具體你再改一改!
<head>
<script language="javascript">
function cha()
{
if (document.f1.te.value == "")
{
alert("請上傳文件!");
return false;
}
else
{
document.f1.submit();
}
}
</script>
</head>
<body onload="document.f1.te.value == ''">
<form name="f1" action="b.jsp" onsubmit="return cha()">
<input type="file" name="upfile" id="uf" onclick="te.value=''" onchange="te.value = uf.value">
<input type="text" name="te" id=te value="" style="visibility:'hidden'"><br>
<input type="submit" name="sub" value="確定"></body>
</form>
</html>
具體你再改一改!
function check(obj)
{
if (obj.upfile.value == "")
{
alert("请选择文件!");
return false;
}
document.form1.submit();
}
</script>
<form name="form1" action="b.jsp" onsubmit="return check(this)">
<!--这里让用户只能通过选择来上传文件,不能输入\粘贴-->
<input type="file" name="upfile" onKeyPress="return false;" onPaste="return false;">
<input type="submit" name="sub" value="确定">
if(document.form1.upfile.value =="")这个判断不管有没有选择过文件都是错的