AJAX——案例

1.商品分类

需求：尽可能同时展示所有商品分类到页面上

步骤：

获取所有的一级分类数据
遍历id，创建获取二级分类请求
合并所有二级分类Promise对象
等待同时成功后，渲染页面

index.html代码

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8" /><meta http-equiv="X-UA-Compatible" content="IE=edge" /><meta name="viewport" content="width=device-width, initial-scale=1.0" /><title>案例_分类导航</title><link rel="stylesheet" href="./css/index.css">
</head><body><!-- 大容器 --><div class="container"><div class="sub-list"><div class="item"><h3>分类名字</h3><ul><li><a href="javascript:;"><img src="http://zhoushugang.gitee.io/erabbit-client-pc-static/uploads/img/category%20(9).png" /><p>巧克力</p></a></li><li><a href="javascript:;"><img src="http://zhoushugang.gitee.io/erabbit-client-pc-static/uploads/img/category%20(9).png" /><p>巧克力</p></a></li><li><a href="javascript:;"><img src="http://zhoushugang.gitee.io/erabbit-client-pc-static/uploads/img/category%20(9).png" /><p>巧克力</p></a></li></ul></div></div></div><script src="https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js"></script><script>/*** 目标：把所有商品分类“同时”渲染到页面上*  1. 获取所有一级分类数据*  2. 遍历id，创建获取二级分类请求*  3. 合并所有二级分类Promise对象*  4. 等待同时成功后，渲染页面*/// 1. 获取所有一级分类数据axios({url:'http://hmajax.itheima.net/api/category/top'}).then(result => {console.log(result)// 2. 遍历id，创建获取二级分类请求const secPromiseList = result.data.data.map(item => {return axios({url:'http://hmajax.itheima.net/api/category/sub',params: {id: item.id  // 一级分类id}})})console.log(secPromiseList) // [二级分类请求Promise对象，二级分类请求Promise对象……]// 3. 合并所有二级分类Promise对象const p = Promise.all(secPromiseList)p.then(result => {console.log(result)// 4. 等待同时成功后，渲染页面const htmlStr = result.map(item => {const dataObj = item.data.data // 取出关键数据对象return `<div class="item"><h3>${dataObj.name}</h3><ul>${dataObj.children.map(item => {return `<li><a href="javascript:;"><img src="${item.picture}"><p>${item.name}</p></a></li>`}).join('')}</ul></div>`}).join('')console.log(htmlStr)document.querySelector('.sub-list').innerHTML = htmlStr})})</script>
</body></html>

index.css代码

* {margin: 0;padding: 0;box-sizing: border-box;
}
a {text-decoration: none;color: #333;
}
ul {list-style: none;
}
.container {width: 980px;margin: 0 auto;
}
.container h3 {font-size: 18px;color: #666;font-weight: normal;text-align: center;line-height: 100px;
}
.container .sub-list {background-color: #fff;
}
.container .sub-list ul {display: flex;padding: 0 32px;flex-wrap: wrap;
}
.container .sub-list ul li {width: 168px;height: 160px;
}
.container .sub-list ul li a {text-align: center;display: block;font-size: 14px;
}
.container .sub-list ul li a img {width: 100px;height: 100px;
}
.container .sub-list ul li a p {line-height: 40px;
}
.container .sub-list ul li a:hover {color: var(--xtx-color);
}
.ref-goods {background-color: #fff;margin-top: 20px;position: relative;
}
.ref-goods .head .xtx-more {position: absolute;top: 20px;right: 20px;
}
.ref-goods .head .tag {text-align: center;color: #999;font-size: 20px;position: relative;top: -20px;
}
.ref-goods .body {display: flex;justify-content: flex-start;flex-wrap: wrap;padding: 0 65px 30px;
}
.ref-goods .body .none {height: 220px;text-align: center;width: 100%;line-height: 220px;color: #999;
}

2.学习反馈-省市区切换

需求：完成省市区切换效果

步骤：

设置省份数据到下拉菜单
切换省份，设置城市数据到下拉菜单，并清空地区下拉菜单
切换城市，设置地区数据到下拉菜单

index.js

/*** 目标1：完成省市区下拉列表切换*  1.1 设置省份下拉菜单数据*  1.2 切换省份，设置城市下拉菜单数据，清空地区下拉菜单*  1.3 切换城市，设置地区下拉菜单数据*/
// 1.1 设置省份下拉菜单数据
axios({url: 'http://hmajax.itheima.net/api/province'}).then(result => {const optionStr = result.data.list.map(pname => `<option value="${pname}">${pname}</option>`).join('')document.querySelector('.province').innerHTML = `<option value="">省份</option>` + optionStr})// 1.2 切换省份，设置城市下拉菜单数据，清空地区下拉菜单document.querySelector('.province').addEventListener('change', async e => {// 获取用户选择省份名字// console.log(e.target.value)const result = await axios({ url: 'http://hmajax.itheima.net/api/city', params: { pname: e.target.value } })const optionStr = result.data.list.map(cname => `<option value="${cname}">${cname}</option>`).join('')// 把默认城市选项+下属城市数据插入select中document.querySelector('.city').innerHTML = `<option value="">城市</option>` + optionStr// 清空地区数据document.querySelector('.area').innerHTML = `<option value="">地区</option>`})// 1.3 切换城市，设置地区下拉菜单数据document.querySelector('.city').addEventListener('change', async e => {console.log(e.target.value)const result = await axios({url: 'http://hmajax.itheima.net/api/area', params: {pname: document.querySelector('.province').value,cname: e.target.value}})console.log(result)const optionStr = result.data.list.map(aname => `<option value="${aname}">${aname}</option>`).join('')console.log(optionStr)document.querySelector('.area').innerHTML = `<option value="">地区</option>` + optionStr})/*** 目标2：收集数据提交保存*  2.1 监听提交的点击事件*  2.2 依靠插件收集表单数据*  2.3 基于axios提交保存，显示结果*/// 2.1 监听提交的点击事件document.querySelector('.submit').addEventListener('click', async () => {// 2.2 依靠插件收集表单数据const form = document.querySelector('.info-form')const data = serialize(form, { hash: true, empty: true })console.log(data)// 2.3 基于axios提交保存，显示结果try {const result = await axios({url: 'http://hmajax.itheima.net/api/feedback',method: 'POST',data})console.log(result)alert(result.data.message)} catch (error) {console.dir(error)alert(error.response.data.message)}})

index.html

<!DOCTYPE html>
<html lang="zh-CN"><head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><!-- 初始化样式 --><link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/reset.css@2.0.2/reset.min.css"><!-- 引入bootstrap.css --><link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/5.2.3/css/bootstrap.min.css" rel="stylesheet"><!-- 核心样式 --><link rel="stylesheet" href="./css/index.css"><title>学习反馈</title>
</head><body><div class="container"><h4 class="stu-title">学习反馈</h4><img class="bg" src="./img/head.png" alt=""><div class="item-wrap"><div class="hot-area"><span class="hot">热门校区</span><ul class="nav"><li><a target="_blank" href="http://bjcp.itheima.com/">北京</a> </li><li><a target="_blank" href="http://sh.itheima.com/">上海</a> </li><li><a target="_blank" href="http://gz.itheima.com/">广州</a> </li><li><a target="_blank" href="http://sz.itheima.com/">深圳</a> </li></ul></div><form class="info-form"><div class="area-box"><span class="title">地区选择</span><select name="province" class="province"><option value="">省份</option></select><select name="city" class="city"><option value="">城市</option></select><select name="area" class="area"><option value="">地区</option></select></div><div class="area-box"><span class="title">您的称呼</span><input type="text" name="nickname" class="nickname"  value="播仔"></div><div class="area-box"><span class="title">宝贵建议</span><textarea type="text" name="feedback" class="feedback" placeholder="您对AJAX阶段课程宝贵的建议"></textarea></div><div class="area-box"><button type="button" class="btn btn-secondary submit">确定提交</button></div></form></div></div><script src="https://cdn.bootcdn.net/ajax/libs/axios/1.2.0/axios.min.js"></script><script src="./js/form-serialize.js"></script><!-- 核心代码 --><script src="./js/index.js"></script>
</body></html>

index.css

.container {width: 1000px;padding-top: 20px;margin: 0 auto 0;position: relative;
}.container .stu-title {font-weight: 900;font-size: 36px;
}.container .bg {display: block;width: 100%;
}.item-wrap .hot-area {display: flex;margin-bottom: 20px;
}.item-wrap .hot-area .hot {color: #c32f32;font-weight: 600;margin-right: 20px;
}.item-wrap .nav {display: flex;
}.item-wrap .nav li {margin-right: 10px;
}.item-wrap .nav li a {text-decoration: none;color: black;
}.item-wrap .title {font-weight: 600;white-space: nowrap;margin-right: 20px;
}.item-wrap select {width: 150px;height: 40px;font-size: 14px;color: black;letter-spacing: 0;font-weight: 400;background: #FFFFFF;border: 1px solid rgba(232, 232, 233, 1);border-radius: 4px;padding: 10px;outline: none;margin-right: 10px;}.item-wrap select option {font-weight: normal;display: block;white-space: nowrap;min-height: 1.2em;padding: 0px 2px 1px;font-size: 16px;}.item-wrap input {font-weight: normal;display: block;white-space: nowrap;min-height: 1.2em;padding: 0px 2px 1px;height: 40px;font-size: 16px;border: 1px solid rgba(232, 232, 233, 0.682);color: black;
}.item-wrap .feedback {width: 400px;height: 150px;border: 1px solid rgba(232, 232, 233, 0.682);
}.item-wrap .area-box {margin-bottom: 20px;display: flex;align-items: center;
}.feedback::-webkit-input-placeholder {/* WebKit browsers */color: #BFBFBF;
}.feedback:-moz-placeholder {/* Mozilla Firefox 4 to 18 */color: #BFBFBF;
}.feedback::-moz-placeholder {/* Mozilla Firefox 19+ */color: #BFBFBF;
}.feedback:-ms-input-placeholder {/* Internet Explorer 10+ */color: #BFBFBF;
}