Loading HTML code in dialog box via AJAX

contents : [
   {
      id : 'plugin_name',
      label : editor.lang.plugin_name.dialogTitle,
      elements :
      [
         {
         type : 'html',
         html : '<div id="results">' + getValidationResult(editor.getData()) + '</div>' // The returned value in getValidationResult is not returned here, the html content in the dialog box is '<div id="result">undefined</div>'
         }
      ]
   }
]

function getValidationResult(data) {
   var httpRequest = (!window.XMLHttpRequest)? new ActiveXObject("Microsoft.XMLHTTP") : new XMLHttpRequest();
   var passingData = "action=analize&content="+escape(data);
   httpRequest.open("POST", "url.jsp", true);
   httpRequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); 
   httpRequest.setRequestHeader("Content-length", passingData.length);
   httpRequest.setRequestHeader("Connection", "close");
   httpRequest.onreadystatechange = function()
   {
      if(httpRequest.readyState == 4)
      {
         var result = httpRequest.responseText;
         // Here, the result variable has the ajax response html
         return result;
      }
   }
   httpRequest.send(passingData);
}