title: Pass parameter from JS to Struts2 Action method
body: <p>The function in my <code>modify.jsp</code> is:</p>
  <pre><code>function getParamList() {
  var accessTypeUnchanged = &quot;0&quot;;
  jPageDialog('Param Setting', '${ctx}/groupportal/functionInfo!detail.do?accessTypeUnchanged='+accessTypeUnchanged, 300, 360);
  }
  </code></pre>
  <p>and The <code>detail()</code> method in <code>FunctionInfoAction.java</code> is:</p>
  <pre><code>@ExecuteResult(name=&quot;index&quot;)
  public String detail(String accessTypeUnchanged) {
  // SOME LOGIC CODE
  return &quot;detail&quot;;
  }
  </code></pre>
  <p>the <code>getter</code> and <code>setter</code> methods have been added, but when I access the <code>getParamList()</code> from web page, a <code>NULLPOINTEREXECEPTION</code> accrued, what's the problem? Actually, the method <code>detail(String accessTypeUnchanged)</code> can't be accessed.</p>