<script language="javascript" type="text/javascript">
function mysubmit(){
………………
if(username==""){alert("用户名不能为空!");return false;}
}
<form name="theform" method ="post" action="1.asp" onsubmit ="return mysubmit();">
<input type=text name="username">
<input type=submit value="提交">
IE浏览器没有问题,但是Firefox浏览器里却不行:文本框里没有填写数据,点击提交也能通过。
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title> <script language="javascript" type="text/javascript">
function mysubmit()
{
var username = document.getElementById("username").value;
if (username == "")
{
alert("用户名不能为空!");
return false;
}
}
</script></head>
<body>
<form name="theform" method="post" action="1.asp" onsubmit="return mysubmit();">
<input type="text" id="username" name="username">
<input type="submit" value="提交">
</form>
</body>
</html>
<input type=text name="username" id="btn">
<input type=submit value="提交">
</form><script language="javascript" type="text/javascript">
function mysubmit(){
var btn = document.getElementById('btn');
if(btn.value == ""){
alert("用户名不能为空!");
return false;
}
}
</script>