title: Uncaught ReferenceError: Sys is not defined on ASP.NET
body: <p>I want use ajax on <a href="http://www.asp.net/" rel="nofollow">ASP.NET</a> platform. For that I use <a href="https://msdn.microsoft.com/en-us/library/bb398863.aspx" rel="nofollow">ScriptManager</a>. Simply I add this script with <a href="https://jquery.com/" rel="nofollow">jQuery</a> after when "<a href="https://learn.jquery.com/using-jquery-core/document-ready/" rel="nofollow">document is ready</a>".</p>
  
  <pre class="lang-javascript prettyprint-override"><code>$(document).ready(function () {
  
      // sync
      {{scopeName}}_init();
  
      // async
  
      Sys.WebForms.PageRequestManager.getInstance().add_pageLoaded(function (sender, args) {
          {{scopeName}}_init();
      });
  
  });
  </code></pre>
  
  <p>And then such a mysterious <a href="https://en.wikipedia.org/wiki/JavaScript" rel="nofollow">javascript</a> error happened.</p>
  
  <blockquote>
    <p>Uncaught ReferenceError: Sys is not defined</p>
  </blockquote>
  
  <p>Q what I have wrong if javascript stop working after first request?</p>