XMLhttpRequest >PHP >XMLhttp请求 [英] XMLhttpRequest > PHP > XMLhttpRequest

问题描述

我还有一个问题.XMLhttpRequests 困扰着我.现在一切都在数据库中，但我需要这些数据在第一次页面加载或重新加载时更新我的​​页面.XHR 在触发 PHP-Script 的 JavaScript 文件中触发.PHP-Script 访问 MySQL 数据库.但是如何将获取的记录返回到我的 JavaScript 中以进行页面更新.我想不通.

I have another question. XMLhttpRequests haunt me. Everything is now in the database but I need this data to update my page on firt page load or reload. The XHR is triggered in JavaScript file which triggers PHP-Script. PHP-Script access MySQL database. But how do I get the fetched records back into my JavaScript for page update. I can not figure it out.

首先是我的同步 XMLhttpRequest:

First my synchronous XMLhttpRequest:

function retrieveRowsDB()
{
  if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari

     xmlhttp=new XMLHttpRequest();

  }
  else
  {// code for IE6, IE5
     xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }

  xmlhttp.open("GET","retrieveRowData.php", false);
  xmlhttp.send(null);

  return xmlhttp.responseText;
}

然后是我的 PHP 脚本:

Then my PHP-Script:

<?php

 $con = mysql_connect("localhost","root","*************");
 if (!$con)
 {
   die('Could not connect: ' . mysql_error());
 }

 mysql_select_db("sadb", $con);

 $data="SELECT * FROM users ORDER BY rowdata ASC";

 if (!mysql_query($data,$con))
 {
  die('Error: ' . mysql_error());
 }
 else
 {
  $dbrecords = mysql_query($data,$con); 
 }

 $rowdata = mysql_fetch_array($dbrecords);

 return $rowdata;

        mysql_close($con);

?>

我在这里错过了什么?有人知道吗?

What am I missing here? Anyone got a clue?

推荐答案

到目前为止，您的代码没有太多技术错误 - 您只需要实际做

There's not much technically wrong with your code so far - you just need to actually do something with it.

在您的 PHP 文件中，您需要以某种方式输出而不是 return $rowdata;.目前，它只是将一个空白文档发送回 javascript，因此您需要 echo 输出代码.通常，当使用多个对象返回给 javascript 时，JSON 是一种很好的格式.查看json_encode.

In your PHP file, instead of return $rowdata;, you need to output it in some way. Currently, it's just sending a blank document back to the javascript, so you'll need to echo out the code. Normally, when using a number of objects to be returned to javascript, JSON is a good format. Check out json_encode.

另一方面，在 js 中，您需要获取响应并以某种方式更新页面.目前，您只是再次退货.

On the other side, in the js, you'll need to take the response and update the page in some manner. Currently, you're just returning it again.

我建议您阅读一些 ajax 教程，并考虑使用诸如 jQuery 之类的框架来完成繁重的工作为你.您可能还想阅读一些关于此主题的内容，因为您有一些基本的误解.

I suggest you go through a few ajax tutorials, and consider using a framework such as jQuery to do the heavy lifting for you. You might also want to do a bit of reading on this topic, as you have some fundamental misconceptions.

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