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This time I will bring you a practical case of using js combined with json to implement ajax. What are the precautions for using js combined with json to implement ajax. The following is a practical case, let’s take a look.
Preparation
1. Install wampserver or other similar software to build a local integrated installation environment. I installed phpstudy
2. HTML, js, css and other files need to be placed in PHPstudy In the WWW directory, the index page
3 and bootstrap.css
are run by default:
phpstudy is very convenient to use, if you If your computer has not installed PHP, you must first configure the system environment variables, add the path to php.exe (find it in the PHPstudy installation directory), and then enter php -v in cmd. The installation version of PHP and other information will appear. The installation is successful.
Then create a new project in the WWW folder of PHPstudy, here I named it AjaxDemo.
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>index</title>
<link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" />
<style>
.container{ width: 50%; margin-top: 30px; }
.text-danger{ margin-top: 6px; }
</style>
</head>
<body>
<p class="container">
<p class="panel panel-default">
<p class="panel-heading">
<p class="panel-title">员工查询</p>
</p>
<p class="panel-body">
<p class="form-horizontal">
<p class="form-group">
<label class="col-md-2 control-label">员工编号：</label>
<p class="col-md-8">
<input type="text" class="form-control" id="keyword">
</p>
<p class="col-md-1">
<button class="btn btn-primary" id="search">查询</button>
</p>
</p>
<p class="form-group">
<label class="col-md-2 control-label">查询结果：</label>
<p class="text-danger col-md-8" id="searchResult"></p>
</p>
</p>
</p>
</p>
</p>
<p class="container">
<p class="panel panel-default">
<p class="panel-heading">
<p class="panel-title">员工增加</p>
</p>
<p class="panel-body">
<p class="form-horizontal">
<p class="form-group">
<label class="col-md-2 control-label">员工编号：</label>
<p class="col-md-8">
<input type="text" class="form-control" id="add-number">
</p>
</p>
<p class="form-group">
<label class="col-md-2 control-label">员工姓名：</label>
<p class="col-md-8">
<input type="text" class="form-control" id="add-name">
</p>
</p>
<p class="form-group">
<label class="col-md-2 control-label">员工性别：</label>
<p class="col-md-8">
<input type="text" class="form-control" id="add-sex">
</p>
</p>
<p class="form-group">
<label class="col-md-2 control-label">员工职位：</label>
<p class="col-md-8">
<input type="text" class="form-control" id="add-job">
</p>
</p>
<p class="form-group">
<p class="col-md-offset-2 col-md-1">
<button class="btn btn-primary" id="add-search">增加员工</button>
</p>
</p>
<p class="form-group">
<label class="col-md-2 control-label">结果：</label>
<p class="text-danger col-md-8" id="add-resultshow"></p>
</p>
</p>
</p>
</p>
</p>
<script src="staffManage.js"></script>
</body>
</html>
staffManage.js
Instantiating Ajax can be divided into five points, which is easier to remember:
1. New an XMLHttpRequest instance Note that it is compatible with lower versions of IE browser
var xhr;
if (window.XMLHttpRequest) {
xhr= new XMLHttpRequest();
} else {
xhr= new ActiveXObject(‘Microsoft.XMLHTTP');
}
2. open(method , url, asyn) The open() method of the XMLHttpRequest object has 3 parameters. The first parameter specifies whether it is GET or POST, the second parameter specifies the URL address, and the third parameter specifies whether to use asynchronous. The default is true, so there is no need to write it.
3*If you make a post request, you must also add the request header setRequestHeader ("Content-Type", "application/x-www-form-urlencoded")
4 , send
Call the send() method to actually send the request. GET requests do not require parameters, and POST requests require the body part to be passed in as a string or FormData object.
5, onReadyStateChange
##6, responseText
// 查询员工方法
var oKeyword=document.getElementById('keyword'), //员工编号
oSearchBtn=document.getElementById('search'), //查询按钮
oSearchRes=document.getElementById('searchResult'); //反馈结果显示
// 查询员工按钮点击事件
oSearchBtn.onclick=function(){
searchStaff();
}
// 创建查询员工方法
function searchStaff(){
//var xhr=new XMLHttpRequest();
//标准写法和IE写法混在一起，可以兼容低版本的IE浏览器
var xhr;
if (window.XMLHttpRequest) {
xhr= new XMLHttpRequest();
} else {
xhr= new ActiveXObject('Microsoft.XMLHTTP');
}
xhr.open('GET','serverjson.php?number='+oKeyword.value);
xhr.send();
//当创建了XMLHttpRequest对象后，要先设置onreadystatechange的回调函数。在回调函数中，通常我们只需通过readyState === 4判断请求是否完成，如果已完成，再根据status === 200判断是否是一个成功的响应。
xhr.onreadystatechange=function(){
if(xhr.readyState==4){
if(xhr.status=200){
var data=JSON.parse(xhr.responseText); //json解析方法JSON.parse 或者 eval('('+xhr.responseText+')')
oSearchRes.innerHTML=data.msg;
}
}
}
}
// 增加员工
var oAddnumber=document.getElementById('add-number'), //员工编号
oAddname=document.getElementById('add-name'), //员工姓名
oAddsex=document.getElementById('add-sex'), //员工性别
oAddjob=document.getElementById('add-job'), //员工职位
oAddSearch=document.getElementById('add-search'), //增加员工按钮
oAddResult=document.getElementById('add-resultshow'); //反馈结果显示
// 增加员工按钮点击事件
oAddSearch.onclick=function(){
createStaff();
}
// 创建增加员工方法
function createStaff(){
var xhr;
if(xhr.XMLHttpRequest){
xhr = new XMLHttpRequest();
}else{
xhr = new ActiveXObject('Microsoft.XMLHTTP');
}
xhr.open('POST','serverjson.php');
//这里注意key=value的等于号两边不要出现空格，会出现错误
var data='name='+oAddname.value
+'&number='+oAddnumber.value
+'&sex='+oAddsex.value
+'&job='+oAddjob.value;
//在open和send之间设置Content-Type
xhr.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
xhr.send(data);
xhr.onreadystatechange=function(){
if(xhr.readyState==4){
if(xhr.status=200){
var data=JSON.parse(xhr.responseText);
if(data.success){
oAddResult.innerHTML=data.msg;
}else{
oAddResult.innerHTML='出现错误：'+data.msg;
}
}else{
alert('发生错误！'+xhr.status)
}
}
}
}serverjson .php
<?php
//设置页面内容是html编码格式是utf-8
header("Content-Type: text/plain;charset=utf-8");
//header("Content-Type: application/json;charset=utf-8");
//header("Content-Type: text/xml;charset=utf-8");
//header("Content-Type: text/html;charset=utf-8");
//header("Content-Type: application/javascript;charset=utf-8");
//定义一个多维数组，包含员工的信息，每条员工信息为一个数组
$staff = array
(
array("name" => "洪七", "number" => "101", "sex" => "男", "job" => "总经理"),
array("name" => "郭靖", "number" => "102", "sex" => "男", "job" => "开发工程师"),
array("name" => "黄蓉", "number" => "103", "sex" => "女", "job" => "产品经理")
);
//判断如果是get请求，则进行搜索；如果是POST请求，则进行新建
//$_SERVER是一个超全局变量，在一个脚本的全部作用域中都可用，不用使用global关键字
//$_SERVER["REQUEST_METHOD"]返回访问页面使用的请求方法
if ($_SERVER["REQUEST_METHOD"] == "GET") {
search();
} elseif ($_SERVER["REQUEST_METHOD"] == "POST"){
create();
}
//通过员工编号搜索员工
function search(){
//检查是否有员工编号的参数
//isset检测变量是否设置；empty判断值为否为空
//超全局变量 $_GET 和 $_POST 用于收集表单数据
if (!isset($_GET["number"]) || empty($_GET["number"])) {
echo '{"success":false,"msg":"参数错误"}';
return;
}
//函数之外声明的变量拥有 Global 作用域，只能在函数以外进行访问。
//global 关键词用于访问函数内的全局变量
global $staff;
//获取number参数
$number = $_GET["number"];
$result = '{"success":false,"msg":"没有找到员工。"}';
//遍历$staff多维数组，查找key值为number的员工是否存在，如果存在，则修改返回结果
foreach ($staff as $value) {
if ($value["number"] == $number) {
$result = '{"success":true,"msg":"找到员工：员工编号：' . $value["number"] .
'，员工姓名：' . $value["name"] .
'，员工性别：' . $value["sex"] .
'，员工职位：' . $value["job"] . '"}';
break;
}
}
echo $result;
}
//创建员工
function create(){
//判断信息是否填写完全
if (!isset($_POST["name"]) || empty($_POST["name"])
|| !isset($_POST["number"]) || empty($_POST["number"])
|| !isset($_POST["sex"]) || empty($_POST["sex"])
|| !isset($_POST["job"]) || empty($_POST["job"])) {
echo '{"success":false,"msg":"参数错误，员工信息填写不全"}';
return;
}
//TODO: 获取POST表单数据并保存到数据库
//提示保存成功
echo '{"success":true,"msg":"员工：' . $_POST["name"] . ' 信息保存成功！"}';
}
?>
Summary
The whole process is roughly as shown in the figure:
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