A user go to search.php and input the term. If the user want to search for an exact prhase it add to the search term " " just like Google do.
But when the variable is passed to search_results.php it look like this:
//search_results.php $var = $_GET['search_field']; echo "User term: " . $var; // display \"apple\" .... MySQL Query =...
I don't know why PHP add that \ to the string.