Can you help me about it?

[Mysterio]

manavworld, i think this will help you:
- - -
$checkit = substr(trim($name),0,6);
if ($checkit == "google")
{
echo "name not allowed";
exit();
}
- - -
now every name like google.com, google.com1, etc, but that starts with "google"... is going to not be allowed.

[strikingv]

better use substr_count()

[Mysterio]

better use substr_count()

give an example