[jQuery] Check if function exists

Hello,

I am loading TinyMCE using the new JQuery Plugin:

<script type="text/javascript">
$().ready(function() {
$('textarea.tinymce').tinymce({
// Location of TinyMCE script
script_url : '../js/tinymce/jscripts/tiny_mce/tiny_mce.js',

Is there a way to load only if tinymce plugin is present without
getting an error?

Basically if I don't want to load the tinymce I just don't load the
plugin ...
... Because I am not able to pass, I think, to my SiteScript.JS file
if I want to load or not the plugin.

Thanks,
Miguel