<script type="text/javascript" >
function hhclick() {
if (document.getElementById('txt').value == "123") {
return true;
}
else {
alert('666');
document.getElementById('txt').focus();
return false;
}
}
</script>
<style type="text/css">
#btn
{
width: 14px;
}
</style>
</head>
<body>
<form id="form1" runat="server">
<div>
<input type="text" id="txt" />
<input type="button" runat="server" id="btn" onclick="if(!hhclick()) {return false;}"
onserverclick="a_Click"/>
</div>
</form>
</body>
cs： protected void a_Click(object sender, EventArgs e)
{
Response.Write("<script>alert('success');</script>");
}