一、常用选择器
image.png
1-1：id选择器，element选择器，.class选择器
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="">
<script src = "./js/jquery-3.4.1.js" type="text/javascript"></script>
<script type="text/javascript">
//jQuary代码的内容
$(document).ready(function(){
//根据id
var username = $("#username");
console.log(username);
//根据class来查询
var areaList = jQuery(".area");
console.log(areaList);
//根据元素标签来查询
var pList = $("p");
console.log(pList)
})
</script>
</head>
<body>
<input type = "text" name="username" id = "username">
<p class="area">广州</p>
<p>深圳</p>
<p class="area">长沙</pm>
<p class="area">北京</p>
</body>
</html>
运行结果
1-2：层级选择器
image.png
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="">
<script src = "./js/jquery-3.4.1.js" type="text/javascript"></script>
<script type="text/javascript">
//jQuary代码的内容
$(document).ready(function(){
//层级选择器 查询body下的所有元素
var bodyList = $('body *');
console.log(bodyList);
//查询body下的所有p元素
var bodyLists = $('body p');
console.log(bodyLists);
//查询body下的直接的p子元素
var bodyLis = $('body > p');
console.log(bodyLis);
//紧贴之后的元素
var input = $("label + input");
console.log(input)
})
</script>
</head>
<body>
<label for="username"> 用户名</label>
<input type = "text" name="username" id = "username">
<input type = "password" name="password" >
<p class="area">广州</p>
<p>深圳</p>
<p class="area">长沙</pm>
<p class="area">北京</p>
<div>
<p>海南</p>
</div>
</body>
</html>
image.png
2-3:伪类选择器
index.html
image.png
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="">
<script src = "./js/jquery-3.4.1.js" type="text/javascript"></script>
<script type="text/javascript">
//jQuary代码的内容
$(document).ready(function(){
//伪类选择器
var pFirst = $("p:first");
console.log(pFirst);
//打印p标签第二个元素
var p2 = $("p:eq(1)");
console.log(p2);
})
</script>
</head>
<body>
<label for="username"> 用户名</label>
<input type = "text" name="username" id = "username">
<input type = "password" name="password" >
<p class="area city">广州</p>
<p>深圳</p>
<p class="area">长沙</pm>
<p class="area">北京</p>
<div>
<p>海南</p>
</div>
</body>
</html>
运行结果
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