<script language="javascript" type="text/javascript">
function isPassword()
{
var val = document.getElementById("pw").value;
var patrn=/^([a-zA-Z]){6,16}$/; //只能输入6-20个字母、数字、下划线;
if (!patrn.exec(val)){
alert("it is wrong");
return false;
}
else{
alert("it is ok");
return true;
}
}
</script>