title: Using indexOf for HTML selection elements via getElementsByTagName
body: <p>Attempting to remove items shown in selects from an array. Here's the <a href="http://jsfiddle.net/cycle4passion/gdr7yrsy/" rel="nofollow" title="JsFiddle">JSFiddle</a></p>
  
  <pre><code>var allProbs = []; // This is defined elsewhere
  var dropProbs = [];
  var j;
  var sel = document.getElementsByTagName("select")
  var selarray = Array.prototype.slice.call(sel); // Convert nodelist to array
  for (j = 0; j &lt; allProbs.length; j++) {
      alert(allProbs[j] + " " + selarray.indexOf(allProbs[j]) ); // all -1 here???
      if (selarray.indexOf(allProbs[j]) == -1) {
          dropProbs[dropProbs.length] = allProbs[j]
      }
  }
  </code></pre>