How to check for empty string and empty search type?

[tony007]

visual ad how to check for m value which is search type ? how to use mysql_escape_string?

It keeps giving me error:
Parse error: syntax error, unexpected in bold parts!

if ( isset($_GET['s']) )
{
$s = $_GET['s'];

if(strlen($s) < 3) )
{
$error = " You can not search for empty string, your search word must be at least 3 character long. Try again please "
}
}