In the system I'm building I use CKEditor for writing posts. Then, when I send it to PHP I validate the html created from CKEditor with HTMLPurifier. The problem is that the HTMLPurifier adds \ before ". For example, the CKEditor produces:
<span style="font-size:36px;">
And after HTMLPurifier:
<span style=\"font-size:36px;\">
I'm using PHP 5.2. Why does HTMLPurifier adds these backslashes and what must I do to fix it?
It's not HTML purifier that adds the extra slashes, but your PHP configuration. Edit php.ini and disable magic_quotes_gpc.
The linked manual suggests you to add the next setting to php.ini:
magic_quotes_gpc = Off
If you are using Apache and can use .htaccess files, create one with:
php_flag magic_quotes_gpc Off
Use stripslashes() to get rid of them.
$string = '<span style=\"font-size:36px;\">';
echo stripslashes($string); // Output: <span style="font-size:36px;">