Detailed explanation of the implementation steps of js encapsulated ajax function-JS Tutorial-php.cn

This time I will bring you a detailed explanation of the implementation steps of the js encapsulated ajax function function. What are theprecautionsfor the js encapsulated ajax function function. The following is a practical case, let's take a look.

AJAX = Asynchronous JavaScript and XML (Asynchronous JavaScript and XML) AJAX is not a newprogramming language, but a new way of using existing standards. It is a synthesis of 7 technologies, which includes seven technologies (javascriptxmlxstlxhtmldomxmlhttprequest,css), ajax is a glue.

Go directly to the program:

js calling part:

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html part:

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ajax encapsulation part:

function ajax(method, url, data, fnsuccess) { var xhr; //1.创建对象，兼容问题 if(window.XMLHttpRequest) { //在高版本的浏览器 IE7+ xhr = new XMLHttpRequest(); //XMLHttpRequest用于在后台与服务器交换数据。这意味着可以在不重新加载整个网页的情况下，对网页的某部分进行更新。 } else { //IE5 IE6 xhr = new ActiveXObject(); } //2.发送请求 //第一个参数：数据传输方式 get post //第二个参数：处理文件 xx.php xx.txt ，要数据：直接写路径就好；提交数据：在地址那里写数据（get方式） //第三个参数：同步或者异步方式，默认是异步true //open //get模式路径上同时加入需要传输的内容 if(method == 'GET' && data) { url = url + '?' + data; } xhr.open(method, url, true); //send //send()如果是get方式，写null或者为空； //如果是post，参数那就直接写要传输的内容 if(method == 'GET') { xhr.send(null); } else { //创建头文件信息 xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded'); xhr.send(data); } //4.接受php传过来的数据，解析 dom操作 xhr.onreadystatechange = function() { if(xhr.readyState == 4) {//响应过程状态信息，4代表发送完成，顺利返回信息 if(xhr.status == 200) {//status:状态码，如果返回的信息是200 fnsuccess && fnsuccess(xhr.responseText); } else { alert(xhr.status);//发生错误时，返回该状态码 } } } }

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Form verification, username verification:

  用户名：
 密码：

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js calling part:

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php part:

该用户名重复了'; }else{ echo '该用户名可以注册'; } ?>

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I believe you have mastered the method after reading the case in this article, For more exciting content, please pay attention to other related articles on the php Chinese website!