How to check if jQuery UI files have been included?
<p>I use a CMS on my website and have run into a problem. The CMS includes jQuery files on some pages, but not on all, and I need to be able to use jQuery everywhere. I found a solution for including the base jQuery library by using the following code:</p>

<pre><code>if(!window.jQuery) 
{
    document.write("&lt;" + "script type='text/javascript' src='https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js'&gt;&lt;/" + "script&gt;");
}
</code></pre>

<p>However, I don't know how to check whether the jQuery UI JS and CSS files have been included or not, specifically these files:</p>

<pre><code>&lt;script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.23/jquery-ui.min.js"&gt;&lt;/script&gt;
&lt;link rel="stylesheet" type="text/css" href="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css"&gt;
</code></pre>

<p>Is there a way to check if those files have been included, similar to the above code for the base jQuery library?</p>
