title: Limited CSS and javascript functionality when publishing website via CMS
body: <p>I'm so new to web development that I'm not exactly sure how to ask this question, but here's the problem I'm facing.</p>
  
  <p>I'm developing a website for a particular department in a university with its own stylesheets that are applied but that I'm unable to edit. I'm trying to make a collage of images for the purpose of site navigation - when you mousehover over an image, I want a different image to be swapped. The first method I used was javascript:</p>
  
  <pre><code>&lt;div class="box"&gt;
  &lt;a target="_blank" href="http://bike.cofc.edu/"&gt;&lt;img src="../biking" onmouseover="this.src='../biking-label'" onmouseout="this.src='../biking'" class="icon" alt="biking" /&gt;&lt;/a&gt; 
  &lt;/div&gt;
  </code></pre>
  
  <p>This worked beautifully within the cms, but when I published the image swap didn't occur - onmouseover caused the first image to disappear but the second image was not called successfully, and onmouseout didn't reverse the broken swap.</p>
  
  <p>I thought that perhaps the university wasn't allowing my javascript, so I tried using just css and html:</p>
  
  <pre><code>span.imgswap-biking {
    background-image:url("");
    background-size:100px 100px; 
    border: 1px solid black;
    background-repeat: no-repeat; display:block;
  }
  span.imgswap-biking:hover img {
    visibility:hidden;
  } 
  &lt;/style&gt;
  &lt;span class="imgswap-biking"&gt;
   &lt;img src="" alt="biking" /&gt;
  &lt;/span&gt;
  </code></pre>
  
  <p>Again, this accomplished the same effect within cms, but when I published, the swap occurred and was reversible, but the background image was not successfully called. I'm afraid that background isn't recognized.</p>
  
  <p>My fundamental confusion is understanding how functionality is lost when publishing websites. I don't really understand what goes on between the time that my site looks good on cms and the time that it is stripped when it is published. General guidance on how to know what sorts of scripts and css changes will work would be helpful if possible. I should mention that I am including css at the top of the webpage because I don't have access to the stylesheet - will the university stylesheet always override mine? Thanks in advance.</p>
  
  <p>Walt</p>