function PageMethod(fn, paramArray, successFn, errorFn)  
{  
  var pagePath = window.location.pathname; 
  if(pagePath.toLowerCase().match("default.aspx") == null)
  {
    if(pagePath.charAt(pagePath.length-1) == "/")
        pagePath = pagePath + "default.aspx";
    else
        pagePath = pagePath + "/default.aspx";
  }
     
  //Create list of parameters in the form:  
//{"paramName1":"paramValue1","paramName2":"paramValue2"}  
  var paramList = '';  
  if (paramArray.length > 0)  
  {  
    for (var i=0; i<paramArray.length; i+=2)  
    {  
      if (paramList.length > 0) paramList += ',';  
      paramList += '"' + paramArray[i] + '":"' + paramArray[i+1] + '"';  
    }  
  }  
  paramList = '{' + paramList + '}';  
  
  //Call the page method  
  $.ajax({  
      type: "POST",  
      url: pagePath + "/" + fn,  
      contentType: "application/json; charset=utf-8",  
      data: paramList,  
      dataType: "json",  
      success: successFn,  
      error: errorFn  
  })  
;}