stripit | secret sauce behind the smashing new chrome extension | Hacking library

You mentioned in a comment that you are using PHP 7.2, so you will have problems using any mysql_ function because this extension is deprecated since 5.5.

You should try using mysqli or PDO instead.

You showed in screenshot that you tried using mysqli_real_escape_string function in line 147 which takes two parameters: 1- the mysqli connection, 2- the string to escape ($data)

You did it like this: $data = mysqli_real_escape_string($_GLOBALS['$con'], $data);

You have two problems here with $_GLOBALS['$con'] it should be $GLOBALS['con'] : the GLOBALS variable without the underscore _ and the key without '$'.

So you should replace the line 147 with:

$data = mysqli_real_escape_string($GLOBALS['con'], $data);

Also I don't know if GLOBALS variable is the safest way to get variables!