![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
天蓬老师Correction status：qualified
Teacher's comments：jquery就的选择器是一个亮点
Collection
Collection
1.id和class选择器：符号标识与css一样
2.标签选择器：除了基本的按标签名选择以外，还有
（1）祖先 后代（2）父 > 子(3)老n + 老（n+1）（4）老n ~ 老n所有弟与妹
示例：
<!doctype html><html lang="en"><head><meta charset="UTF-8"><meta name="viewport"content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0"><meta http-equiv="X-UA-Compatible" content="ie=edge"><script type="text/javascript" src="../jquery-3.4.1.js"></script><title>jquery基本选择器--6种</title><style>div{width: 400px;height: 150px;}.p1{background: yellow;}.p2{background: yellowgreen;}</style></head><body><div style="background:red;">div1<p class="p1">1</p><p class="p2">2</p><input type="text" id="user"><input type="text"></div><div style="background:green;">div2<p class="p1">I<input type="text"></p><p class="p2">II</p></div><div style="background:blue;">div3<p class="p1">甲</p><p class="p2">乙</p></div><button onclick="tag()">按标签选</button><button onclick="qClass()">按class选</button><button onclick="grandTag()">标签下的所有子孙标签</button><button onclick="sonTag()">标签下的所有子标签</button><button onclick="bro1()">标签后面紧跟的某标签</button><button onclick="broAll()">标签后面所有的兄弟标签</button><script type="text/javascript">function tag() {return $("p").css("fontsize","50px");// var p1 = $('p').val();// alert(p1);}function qClass() {var p2 = $('.p2');var arg2 = $("#user");console.log(p2);console.log(arg2);}function grandTag() {var arg3 = $('div input ');console.log(arg3);}function sonTag() {var arg4 = $('div > input ');console.log(arg4);}function bro1() {var arg5 = $('p + input ');console.log(arg5);}function broAll() {var arg6 = $('p ~ input ');console.log(arg6);}</script></body></html>