If you have a Joomla! 1.5 site with Frontpage Slideshow v3.x installed, you may have noticed that your slideshows are broken in Firefox 20 or newer.
First let me clarify that this occurs only in Joomla! 1.5, with the Mootools Upgrade plugin enabled and in Firefox version 20 or newer.
This is because Firefox 20 (when launched) introduced an improvement into its JavaScript rendering engine that caused conflicts in Mootools 1.2.x (which is used in Joomla! 1.5 with the Mootools Upgrade plugin enabled).
The Mootools team wrote about this bug and even released an updated to Mootools 1.2.x itself to address the issue:
mootools.net/blog/2013/02/19/mootools-1-2-6-released/
However, since Joomla! 1.5 is considered obsolete by the Joomla! core team, it will not be updated.
This whole Mootools/Firefox 20+/Joomla! 1.5/"Mootools Upgrade plugin" issue is of course not affecting only Frontpage Slideshow, but other extensions in Joomla! that use specific JavaScript code.
To fix this, simply edit your Joomla! template's main index.php file and add the following piece of code, RIGHT AFTER the opening <head> tag:
<script>delete String.prototype.contains;</script>
This will fix any JavaScript issues you had with Frontpage Slideshow and other extensions, cause of this Mootools originating problem.
