Programatically remove <script src="/unwanted.js".. /> reference
<p>I have partial control of a web page where by I can enter snippets of code at various places, but I cannot remove any preexisting code.</p>

<p>There is a script reference midway through the page</p>

<pre><code>&lt;script src="/unwanted.js" type="text/javascript"&gt;&lt;/script&gt;
</code></pre>

<p>but I do not want the script to load. I cannot access the <code>unwanted.js</code> file. Is there anyway I can use javascript executing above this refernce to cause the <code>unwanted.js</code> file not to load?</p>

<p><strong>Edit</strong>: To answer the comments asking what and why:</p>

<p>I'm setting up a Stack Exchange site and the WMD* js file loads halfway down the page. SE will allow you to insert HTML in various parts of the page - so you can have your custom header and footer etc. I want to override the standard WMD code with my own version of it. 
I can get around the problem by just loading javascript after the original WMD script loads and replacing the functions with my own - but it would be nice not to have such a large chunk of JS load needlessly.</p>

<p>*WMD = the mark down editor used here at SO, and on the SE sites.</p>
