PHP：验证表单并显示警报

Question

I have a registration form in which i have a field login name. I want unique login name for every user so whenever user click a button i want to check database. If the login name entered by user is already present, i want to display an alert box asking him to try another login name. I wrote the following code.

if($login != '')
{
$query = "Select LoginName from register where LoginName='".$login."'";
$result = mysql_query($query);
if($result)
{
?>
<script type="text/javascript">
alert("Login name exist");
</script>
<?php
}
else
{
insert into database
}
}

The problem here is every time it shows me an alert for the name already exists.It never goes into the else part. Please help me about this

Answer 1

first when you fetch data then count $rows array check if count is greater that 0 then u display error msg "username already exists"

so put if condition and in else write insert data

Enjoy :)