title: Multiple select, when one certain option is selected, unselect other options
body: <p>I have a multiple select list in my HTML. If value 296 gets selected, all the other options must get unselected.</p>
  
  <p>This is the code I am using so I don't have to use CTRL when I want to select multiple options:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>$("#select").mousedown(function(e) {
    e.preventDefault();
  
    var select = this;
    var scroll = select.scrollTop;
  
    if (select.value == 296) {
      //unselect all the other options
    }
  
    e.target.selected = !e.target.selected;
  
    setTimeout(function() {
      select.scrollTop = scroll;
    }, 0);
  
    $(select).focus();
  }).mousemove(function(e) {
    e.preventDefault()
  });</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"&gt;&lt;/script&gt;
  &lt;select id="select" name="adrestype_id" class="form-control" required="required" multiple="multiple"&gt;                
      &lt;option value="296"&gt;Primairadres &lt;/option&gt;                
      &lt;option value="297"&gt;Bezoekadres &lt;/option&gt;                
      &lt;option value="298"&gt;Factuuradres &lt;/option&gt;                
      &lt;option value="299"&gt;Postadres &lt;/option&gt;
  &lt;/select&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>I can't seem to figure out how I can unselect all the other options when value 296 is selected</p>