javascript - onreadystatechange 里面应该有什么？

Question

我有一个问题。我在我用来触发的外部 javascript (ajax) 中有一个删除函数，以便执行我的 PHP 文件中的删除查询。

我想知道的是 onreadystatechange 函数中应该有什么。之前有一个功能只是显示表格。 onreadystatechange函数里面是

document.getElementById("divTable").innerHTML=xmlhttp.responseText;

所以现在我很困惑，我是放同样的东西还是？删除记录后如何让查询执行并在表中显示新结果？

function.js Javascript 文件:

function deleteThis(count){

 var name = document.getElementById("row"+count).innerHTML;
 var page = "database.php";
 var parameters = 'name='+name+'&action=delete'
 var xmlhttp = new XMLHttpRequest();

 if(confirm('Are you sure you want to delete this?')==true){

 if(xmlhttp==null){
  alert("Your browser does not support ajax!");
  return false;
  }
 xmlhttp.onreadystatechange=function(){
 //what should be in here
 };
  xmlhttp.open("GET", page+"?"+parameters, true);
  xmlhttp.send(null);
 }
}

在 database.php 文件中:

                      .
                      .
               Other lines of code
                      .
                      .


 function deleteRow($name){
    $table_info = "info";

  $query_string = "delete from $table_info where id = '$name'";
  $result = @mysql_query($query_string);
 }
?>

<?php
  $name = rtrim($_REQUEST['name']);
  $action = rtrim($_REQUEST['action']);

  if($action=="delete"){
   echo deleteRow($name);
  }
  else{
   echo update_database();
  }
?>

Answer 1

来自 MDN

Returns a EventHandler that is called whenever the readyState attribute changes. The callback is called from the user interface thread.

所以当readyState改变时，你可以在这个属性中看到请求的状态。

0 UNSENT open() has not been called yet.

1 OPENED send() has been called.

2 HEADERS_RECEIVED send() has been called, and headers and status are available.

3 LOADING Downloading; responseText holds partial data.

4 DONE The operation is complete.