innerHTML.value不起作用？

Question

I've been trying to write a JavaScript program that returns Wikipedia search results. A few days ago, I got it to the point where I could see the item being searched for, as confirmed by the alert() method, but now when I call the same alert() method it just returns "undefined":

$("button").click(function(e){
  var search =document.getElementById("test").innerHTML.value;
        alert(search);
 });

I swear that this is exactly what I had while it was working, so there must be some subtle issue elsewhere. Any help is appreciated, complete code below:

HTML:

  <a href="http://en.wikipedia.org/wiki/Special:Random">Random</a>
  <section>
  <form>
  <br>
  <div class="divid">
       <input type="text" value=''  id="test" >
       <button >Search</button>
  </div>
  </form>

  <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
  <script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.11.3/jquery-ui.min.js"></script>

JavaScript:

   $(document).ready(function () {

   $("button").click(function(e){
   var search =document.getElementById("test").innerHTML.value;
       alert(search);
   });

   var button = $('button');
   var toSearch = '';
   var searchUrl = "http://en.wikipedia.org/w/api.php"
   var x="England"; 

   input.autocomplete({
    source: function (request, response) {
        $.ajax({
            url: searchUrl,
            dataType: 'jsonp',
            data: {
                'action': "opensearch",
                'format': "json",
                'search': request.term
            },
            success: function (data) {
                response(data[1]);
            }
        });

        }

       });      


    var playListURL = 'http://en.wikipedia.org/w/api.php?format=json&action=query&titles=India&prop=revisions&rvprop=content&callback=?';
    $.getJSON(playListURL ,function(data) {
       $.each(data.query.pages, function(i, item) {
         //alert(item.title);
       })
    })

     $.ajax({  
//http://en.wikipedia.org/w/api.php?format=json&action=query&titles=India&prop=revisions&rvprop=content&callback=?
   url: '//en.wikipedia.org/w/api.php',
   data: { action: 'query', list: 'search', srsearch: "Carl Sagan", format: 'json' },
    dataType: 'jsonp',
    success: 
     function (x) {
       //alert( x.query.search[0].title);
   }
 });

  })    

Answer 1

• Use .innerHTML to get the html in a DOM element
• Use .value to get the value of an input, textarea, or other form input

.innerHTML.value is not a thing.