string preg_quote ( string $str [, string $delimiter] );
preg_quote() takes str and puts a backslash in front of every character that is part of the regular expression syntax.
Following is the piece of code, copy and paste this code into a file and verify the result.
<?php $keywords = '$40 for a g3/400'; $keywords = preg_quote($keywords, '/'); echo $keywords; ?>
This will produce the following result −
\$40 for a g3\/400