各位高手帮忙研究以下这段代码

function newXMLHttp()
{
 var XMLHttp=null;
 if (window.XMLHttpRequest)
 {
  XMLHttp=new XMLHttpRequest();
 }
 if(XMLHttp==null && window.ActiveXObject)
 {
  var clsids = ["MSXML2.XMLHttp.5.0","MSXML2.XMLHttp.4.0","MSXML2.XMLHttp.3.0","MSXML2.XMLHttp.2.0","MSXML2.XMLHttp.1.0","MSXML2.XMLHttp","Microsoft.XMLHttp"];
  for(var i=0; i<clsids.length && XMLHttp == null; i++)
  {
  try
  {
  XMLHttp = new ActiveXObject(clsids[i]);
  }
  catch(e)
  {}
  }
 }
 return XMLHttp;
}//POST页面
function postHTML(URL,data,func)
{
  try
  {
  var XMLHttp=newXMLHttp();
 //同步调用
 if(typeof(func)!="function")
 {
  XMLHttp.open("POST",URL, false);
  XMLHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
  XMLHttp.send(data);  var result = XMLHttp.status;  
  var responseText=XMLHttp.responseText;
    
  if(result==200)
  {
  return responseText;
  }
  else
  {
  return false;
  }   
 }
 //异步调用
 else
 {
      XMLHttp.onreadystatechange = function()
      {
          if (XMLHttp.readyState == 4)
          {
              if (XMLHttp.status == 200)
                  {
                  var responseText = XMLHttp.responseText ;
                  func(responseText);
                  }
              else
                  {
                  func(false);
                  }
          }
      }
      XMLHttp.open("POST",URL, true);
      XMLHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
      XMLHttp.send(data);   
 }
  }
  catch(e){}
}
 
 //led生产任务加工数据类
        
       TempData=function TemDatalist2(start,ref_data,_count,_intstr)
       {
          this.Model=function(td1,td2,td3,td4)//实体类表示每一条生产任务
           {
               this.Td=new Array (td1,td2,td3,td4);
              
               function(index)
               {
                  return  this.Td[index];
               }
           }
          if(ref_data!=null&&ref_data!="")
          {
               this.DataList=new Array()
               if((_count-start)>=_intstr)
                {
                   for(var i=0;i<_intstr;i++)
                     {
                         var data=new this.Model(ref_data[(start-1)*4+(i*4)],ref_data[(start-1)*4+(i*4)+1],ref_data[(start-1)*4+(i*4)+2],ref_data[(start-1)*4+(i*4)+3])
                         this.DataList.push(data);
                     }
                 }
               else
               {
                   
                   if(_count<=_intstr)
                   { 
                        start=1;
                        for(var i=0;i<_intstr;i++)
                         {
                            var data=new this.Model(ref_data[(start-1)*4+(i*4)],ref_data[(start-1)*4+(i*4)+1],ref_data[(start-1)*4+(i*4)+2],ref_data[(start-1)*4+(i*4)+3])
                             this.DataList.push(data);       
                         }
                   }
                   else
                   {
                      
                        for(var i=0;i<_intstr;i++)
                         {
                           if((_count-start)>=i)
                           {
                               var data=new this.Model(ref_data[(start-1)*4+(i*4)],ref_data[(start-1)*4+(i*4)+1],ref_data[(start-1)*4+(i*4)+2],ref_data[(start-1)*4+(i*4)+3])
                               this.DataList.push(data);
                           }
                           else
                           { 
                               var data=new this.Model(ref_data[(i-(_count-start))*4],ref_data[(i-(_count-start))*4+1],ref_data[(i-(_count-start))*4+2],ref_data[(i-(_count-start))*4+3])
                               this.DataList.push(data);
                           }
                         }
                  }
               }
              return this.DataList;
           }
           else
          {
             return null;
          }
         
       }
function Setdate(start,end,ref_data,_count,head_name)//设置显示的数据
           {
                var data=TempData(start,ref_data,_count,end);
                 if(data!=null)
                 {
                     for(var i=0;i<end;i++)
                     {
                         for(var j=1;j<5;j++)
                         {
                             var name=head_name+(i*4+j);
                             var td= document.getElementById(name);
                             td.innerText=data[i].Td[j-1]==null? "/":data[i].Td[j-1];
                         }
                     }
                 }
                 else
                 {
                     for(var i=0;i<end;i++)
                     {
                         for(var j=1;j<5;j++)
                         {
                             var name=head_name+(i*4+j);
                             var td= document.getElementById(name);
                             td.innerText="/";
 
                         }
                     }
                 }
            }