title: Knockout array subscription not working
body: <p>I have been trying for a few days now to have Knockout raise an event every time a 'zip code' value changes on a list of people lines. I've tried various ways to achieve this behaviour but just can't seem to get it right. Currently, this is the Html that I have: -</p>
  
  <pre><code>&lt;table&gt;
      &lt;thead&gt;
          &lt;tr&gt;
              &lt;th&gt;First name&lt;/th&gt;
              &lt;th&gt;Last Name&lt;/th&gt;
              &lt;th&gt;Age&lt;/th&gt;
              &lt;th&gt;Zip Code&lt;/th&gt;
          &lt;/tr&gt;
      &lt;/thead&gt;
      &lt;tbody data-bind="foreach: people"&gt;
          &lt;tr&gt;
              &lt;td data-bind="text: firstName"&gt;&lt;/td&gt;
              &lt;td data-bind="text: lastName"&gt;&lt;/td&gt;
              &lt;td data-bind="text: age"&gt;&lt;/td&gt;
              &lt;td &gt;&lt;input id="zipCodInput" data-bind="value: zipCode" /&gt;&lt;/td&gt;
          &lt;/tr&gt;
      &lt;/tbody&gt;
  &lt;/table&gt;
  &lt;/body&gt;
  </code></pre>
  
  <p>And this is the script that I have which populates the table: -</p>
  
  <pre><code>&lt;script&gt;
      jQuery(document).ready(function () {
  
          // Ultimately will come from an Ajax call
          //var result = $.ajax({
          //    type: "GET",
          //    url: "/api/Resource",
          //    async: false
          //}).responseText;
  
          // Hard coded array for testing
          var result = [{ "firstName": "Jimmy", "lastName": "Smith", "age": "43", "zipCode": "" },
          { "firstName": "John", "lastName": "Jones", "age": "23", "zipCode": "" },
          { "firstName": "Sarah", "lastName": "Palmer", "age": "26", "zipCode": "GH7HU" },
          { "firstName": "Fred", "lastName": "Smith", "age": "34", "zipCode": "" },
          { "firstName": "Simon", "lastName": "Davis", "age": "53", "zipCode": "" }];
  
          function viewModel() {
              var myArray = ko.observableArray(result);
  
              myArray.subscribe(function (changes) {
                  console.log(changes);
              }, null, "arrayChange");
  
              people = myArray;
          };
  
          ko.applyBindings(new viewModel());
      });
  &lt;/script&gt;
  </code></pre>
  
  <p>It binds the data correctly, but I never get any changes logged when editing the zip code lines on the page. Any idea how I can amend or rewrite the code to be able to trap those changes?</p>
  
  <p>Ultimately I want to add only changed lines into a json array to post back server side. </p>
  
  <p>Thank you.</p>