源码地址：

​​https://github.com/huangguangda/Ajaxitm​​

什么是Ajax技术？实战中的运用ajax技术，了解前后端交互的方式，了解移动端的模式，了解H5的新技术，了解CSS3的使用，和JQuery的使用。

Ajax技术可以提高用户体验，无刷新的与后台进行数据的交互，异步的操作方式，可以不用刷新页面提高性能。

了解前后端的交互流程，主要分为三部分，客户端，服务端，数据库，环境搭建，wamp，phpMyAdmin。

【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_json

wamp，window，Apache，mysql，php。

创建项目：

【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_json_02

创建一个名为AjaxItem的小项目

【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_sql_03

接下来附上我的代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form>
    用户名：<input type="text">
    <input type="submit" value="注册">
</form>
</body>
</html>


运行起来的效果是如下截图

【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_php_04

添加一个服务端跳转的页面reg.php，服务端要找到输入框的值

提交表单方式：GET，POST

指定当前页的编码

header("Content-type:text/html;charset=utf-8");


连接数据库mysql

$con = mysql_connect();


默认值：config.default.php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="reg.php">
    用户名：<input type="text" name="username">
    <input type="submit" value="注册">
</form>
</body>
</html>


2

get提交的特点：

【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_sql_05

【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_json_06

post提交的特点：

【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_html_07

上面截图可以看出传输数据的区别，我们一般对于数据的查询，尽量采用get的方式，而我们要对数据的修改，添加或者是删除，我们可以用post比较好一点。

服务端的书写：

选择数据库：mysql_select_db();建立数据库，建表，键字段

指定数据库的编码格式

mysql_query("set names utf8");

获取传输数据

$_GET
$_POST


创建数据库：

【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_php_08

创建表：

【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_php_09

【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_json_10

创建数据

【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_sql_11

sql查询：

select * from 表 where 字段 = 值
mysql_query
mysql_num_rows


reg.php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="reg.php" method="post">
    用户名：<input type="text" name="username">
    <input type="submit" value="注册">
</form>
</body>
</html>


index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="reg.php" method="post">
    用户名：<input type="text" name="username">
    <input type="submit" value="注册">
</form>
</body>
</html>


reg.php代码：

<?php
// 定义编码格式
header("Content-type:text/html;charset=utf-8");
// 连接mysql
$con = mysql_connect("localhost",'root','123456');
mysql_select_db('ajaxitem');
mysql_query('set names utf8');

$username = $_POST['username'];
$sql = "select * from reg where username = '$username'";
$query = mysql_query($sql);

// 如何区分查询到还是没有查询到呢？
//mysql_num_rows($query);
// 找到为1，没有找到为0

if($query && mysql_num_rows($query)){
 echo "<script>alert('已经有人注册过了')</script>";
 echo "<script>history.back()</script>";
}else {
$sql = "insert into reg(username) values ('$username')";
$sql = mysql_query($sql);
if($query){
    echo "<script>alert('注册成功')</script>";
    echo "<script>window.location = 'index.html'</script>";
}
}
?>


【达达前端】Ajax实战项目源码讲解（快速入门的实例）Github源码_sql_12

: 3

sql查询：

select * from 表 where 字段 = 值
mysql_query
mysql_num_rows

sql添加

insert into 表（字段）values（值）


Ajax基本使用：

XMLHttpRequest
open
onreadystatechange

readyState
0未初始化
1初始化
2发送数据
3数据传送中
4完成

send
onreadystatechange

status
http状态码
200
301
304
403
404
500

statusText
responseText
 responseXML
 JSON.parse

POST方式：
需要设置头信息
位置在send前

setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
setRequestHeader(‘Content-Type’, ‘application/json’);

JSON_stringify
JQuery中的Ajax

$.ajax

url
type
data
success
error
dataType
async


提供公共代码

require_once()

获取数据
mysql_fetch_row
mysql_fetch_assoc
mysql_fetch_array
mysql_fetch_object

增删改查
delete from 表 where 字段 = 值
update 表 set 字段 = 新值 where id = $id;
Functions to create xhrs

function createStandardXHR() {
 try {
  return new window.XMLHttpRequest();
 }catch(e){}
}

function createActiveXHR() {
 try {
  return new window.ActiveXObject("Microsoft.XMLHTTP");
  }catch(e){}
}


index.html代码：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="reg.php" method="post">
    用户名：<input type="text" name="username">
    <input type="submit" value="注册">
</form>
<div id="div">

</div>
<script>
var oInput = document.getElementById("input1");
var oDiv = document.getElementById('div1');

oInput.onblur = function () {
    var xhr = new XMLHttpRequest();
    xhr.open('POST','user.php',true);

}
</script>
</body>
</html>


user.php

<?php
// 定义编码格式
header("Content-type:text/html;charset=utf-8");
// 连接mysql
$con = mysql_connect("localhost",'root','123456');
mysql_select_db('ajaxitem');
mysql_query('set names utf8');

$username = $_GET['username'];
$sql = "select * from reg where username = '$username'";
$query = mysql_query($sql);

if($sql && mysql_num_rows($query)){
    echo '{"code":0, "message": "已经有人注册过啦" }';
}else {
    echo  '{"code":1,"message":"可以注册"}';
}
?>


index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="reg.php" method="post">
    用户名：<input type="text" name="username">
    <input type="submit" value="注册">
</form>
<div id="div">

</div>
<script>
var oInput = document.getElementById("input1");
var oDiv = document.getElementById('div1');

oInput.onblur = function () {
    var xhr = new XMLHttpRequest();
    // xhr.open('POST','user.php?username='+encodeURIComponent(this.value),true);
    xhr.open('POST','user.php',true);

    // 监听整个流程，多次触发
    xhr.onreadystatechange = function () {
        if(xhr.readyState == 4) {
            if(xhr.status == 200) {
                xhr.responseText;
                // xhr.responseXML
                // console.log(JSON.parse(xhr.responseText));
                var obj = JSON.parse(xhr.responseText);
                if(obj.code) {
                    oDiv.innerHTML = obj.message
                }else {
                    oDiv.innerHTML = obj.message
                }
            }
        }
    };
    // xhr.send(null);
    xhr.send('username'+encodeURIComponent(this.value));
}
</script>
</body>
</html>


index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="reg.php" method="post">
    用户名：<input type="text" name="username">
    <input type="submit" value="注册">
</form>
<div id="div">

</div>
<script>
var oInput = document.getElementById("input1");
var oDiv = document.getElementById('div1');

oInput.onblur = function () {
    var xhr = new XMLHttpRequest();
    // xhr.open('POST','user.php?username='+encodeURIComponent(this.value),true);
    xhr.open('POST','user.php',true);

    // 监听整个流程，多次触发
    xhr.onreadystatechange = function () {
        if(xhr.readyState == 4) {
            if(xhr.status == 200) {
                xhr.responseText;
                // xhr.responseXML
                // console.log(JSON.parse(xhr.responseText));
                var obj = JSON.parse(xhr.responseText);
                if(obj.code) {
                    oDiv.innerHTML = obj.message
                }else {
                    oDiv.innerHTML = obj.message
                }
            }
        }
    };
    // xhr.send(null);
    // xhr.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
    // xhr.send('username'+encodeURIComponent(this.value));

    // 'username=dada&age=12'
    // xhr.setRequestHeader('Content-Type','application/json');
    // xhr.send('{ "username": dada, "age": 12}');
    // xhr.send(JSON.stringify({"username":"dada","age":12}));

    // {"username":"dada","age":12} -> $.param() -> "useranme=dada&age=12"
}
</script>
</body>
</html>


JQuery:

if(s.data && s.processData && typeof s.data !== "string"){
 s.data = JQuery.param(s.data, s.traditional);
}

inspectPrefiltersOrTransports(prefilters, s, options, jqXHR);

if(state === 2){
return jqXHR;
}


ajax.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
$.ajax({
 url: 'jquery.php',
 type:  'GET',
 data: {username: "dada"},
 success: function(data){
  console.log(data);
 }
});
</body>
</html>


jquery.php

<?PHP

  //echo 'red';
  echo '{"color":"red","width":"200px"}';

?>


请求相同部分：

require_once(‘connect.php');


ajax1.html

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<script>
//get : http://localhost/reg.php?username=dada
//post : http://localhost/reg.php
</script>
</head>

<body>
<form action="reg.php" method="post">
  用户名 : <input type="text" name="username">   <!--username=dada-->
    <input type="submit" value="注册">
</form>
</body>
</html>


ajax2.html

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>

</head>

<body>
<form action="reg.php" method="post">
  用户名 : <input id="input1" type="text" name="username">   <!--username=dada-->
    <input type="submit" value="注册">
</form>
<div id="div1"></div>
<script>
var oInput = document.getElementById('input1');
var oDiv = document.getElementById('div1');

oInput.onblur = function(){
  var xhr = new XMLHttpRequest();
  xhr.open('GET','user.php?username='+encodeURIComponent(this.value),true);
  xhr.onreadystatechange = function(){
    
    if(xhr.readyState == 4){
      //console.log(xhr.status);
      //console.log(xhr.statusText);
      if(xhr.status == 200){
        //console.log(xhr.responseText);
        //console.log(JSON.parse(xhr.responseText));
        var obj = JSON.parse(xhr.responseText);
        if(obj.code){
          oDiv.innerHTML = obj.message;
        }
        else{
          oDiv.innerHTML = obj.message;
        }
      }
    }
    
  };
  xhr.send(null);
};
</script>
</body>
</html>


ajax3.html

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>

</head>

<body>
<form action="reg.php" method="post">
  用户名 : <input id="input1" type="text" name="username">   <!--username=dada-->
    <input type="submit" value="注册">
</form>
<div id="div1"></div>
<script>
var oInput = document.getElementById('input1');
var oDiv = document.getElementById('div1');

oInput.onblur = function(){
  var xhr = new XMLHttpRequest();
  xhr.open('POST','user.php',true);
  xhr.onreadystatechange = function(){
    
    if(xhr.readyState == 4){
      //console.log(xhr.status);
      //console.log(xhr.statusText);
      if(xhr.status == 200){
        //console.log(xhr.responseText);
        //console.log(JSON.parse(xhr.responseText));
        var obj = JSON.parse(xhr.responseText);
        if(obj.code){
          oDiv.innerHTML = obj.message;
        }
        else{
          oDiv.innerHTML = obj.message;
        }
      }
    }
    
  };
  //xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
  //xhr.send('username='+encodeURIComponent(this.value));
  
  //'username=dada&age=12'
  
  //xhr.setRequestHeader('Content-Type', 'application/json');
  //xhr.send('{"username":"dada","age":12}');
  //xhr.send(JSON.stringify({"username":"dada","age":12}));
  
  //{"username":"dada","age":12} ->  $.param()  ->  'username=dada&age=12'
  
};
</script>
</body>
</html>


ajax4.html

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<script src="jquery-2.1.3.min.js"></script>
<script>

$.ajax({
  url : 'jquery.php',
  type : 'POST',
  data : {username:"dada"},
  dataType : 'json',
  async : false,
  success : function(data){   //xhr.responseText
    console.log(data);
    //var obj = JSON.parse(data);
    //console.log(obj);
  },
  error : function(err){
    console.log(err.status);
    console.log(err.statusText);
  }
});
console.log(123);
</script>
</head>

<body>
</body>
</html>


ajax5.html

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<script src="jquery-2.1.3.min.js"></script>
<script>

$.ajax({
  url : 'data.php',
  type : 'POST',
  data : {username:"dada"},
  dataType : 'json',
  async : false,
  success : function(data){   //xhr.responseText
    console.log(data);
    //var obj = JSON.parse(data);
    //console.log(obj);
  },
  error : function(err){
    console.log(err.status);
    console.log(err.statusText);
  }
});
console.log(123);
</script>
</head>

<body>
</body>
</html>


connect.php

<?PHP

  header("Content-type: text/html; charset=utf-8");
  $con = mysql_connect('localhost','root','');
  mysql_select_db('ajaxitem');
  mysql_query('set names utf8');

?


data.php

<?PHP

  require_once('connect.php');
  
  //$sql = "delete from reg where username = 'da1'";
  //$query = mysql_query($sql);
  
  $sql = "update reg set username = 'da1' where id = 4";
  $query = mysql_query($sql);
  
  $sql = "select * from reg limit 2";
  $query = mysql_query($sql);
  
  //print_r($query);
  //print_r(mysql_num_rows($query));
  
  //$row = mysql_fetch_row($query);
  //print_r($row);
  
  /*while($row = mysql_fetch_row($query)){    //数组下标的方式输入
    print_r($row);
  }*/
  
  /*while($row = mysql_fetch_assoc($query)){    //数组键值的方式输入
    print_r($row);
  }*/
  
  /*while($row = mysql_fetch_array($query)){    //数组整体的方式输入
    print_r($row);
  }*/
  
  /*while($row = mysql_fetch_object($query)){    //对象键值的方式输入
    print_r($row);
  }*/
  /*while($row = mysql_fetch_assoc($query)){    //数组键值的方式输入
    print_r($row['username']);
  }*/
  /*while($row = mysql_fetch_object($query)){    //对象键值的方式输入
    print_r($row -> username);
  }*/
  while($row = mysql_fetch_assoc($query)){    //数组键值的方式输入
    $data[] = $row;
  }
  
  //print_r(json_encode($data));
  
  echo json_encode($data);
  
?>


user.php

<?PHP

  require_once('connect.php');
  
  $username = $_REQUEST['username'];
  
  $sql = "select * from reg where username = '$username'";
  $query = mysql_query($sql);
  
  if($query && mysql_num_rows($query)){
    echo '{"code":0 , "message" : "已经有人注册过啦"}'; 
  }
  else{
    echo '{"code":1 , "message" : "可以注册"}'; 
  }

?>


jquery.php

<?PHP

  //echo 'red';
  echo '{"color":"red","width":"200px"}';

?>


reg.php

<?PHP

  //username -> hello
  
  require_once('connect.php');

  $username = $_POST['username'];
  $sql = "select * from reg where username = '$username'";
  $query = mysql_query($sql);
    
  if($query && mysql_num_rows($query)){
    echo "<script>alert('已经有人注册过啦')</script>";
    echo "<script>history.back()</script>";
  }
  else{
    $sql = "insert into reg(username) values('$username')";
    $query = mysql_query($sql);
    if($query){
      echo "<script>alert('注册成功')</script>";
      echo "<script>window.location = 'index.html'</script>";
    }
  }

?>