mysqli_real_escape_string mysqli链接？

Question

I get "Notice: Undefined variable: con in C:\\wamp\\www\\Game\\functions.php on line 8" when trying to use the function, here's the code.

function protect($string) {
return mysqli_real_escape_string($con,strip_tags(addslashes($string)));
}

I use the $con for my queries and it's fine so I thought that was what was for this mysqli part?

This is for registration, I have some registration that is working but I can't use that, here's a confirmed working line

$res=mysqli_query($con,$sql);

Any ideas?

Answer 1

$con doesn't exist in the function protect() , so you either need to make $con global:

global $con = mysqli_connect();

or you need to pass $con as an argument:

function protect($string, $con) {
    return mysqli_real_escape_string($con,strip_tags(addslashes($string)));
}

Answer 2

ANSWER FROM MIHAI

mysqli_real_escape_string needs a connection BEFORE it can function,use global $con; as the first line in your function. – Mihai