标签：选择器 eva 偶数 js代码 大于 focus evo file rip
"""
jQuery内部封装了原生的js代码(还额外添加了很多的功能)
能够让你通过书写更少的代码 完成js操作
类似于python里面的模块 在前端模块不叫模块 叫 “类库”
兼容多个浏览器的 你在使用jQuery的时候就不需要考虑浏览器兼容问题
jQuery的宗旨
write less do more
让你用更少的代码完成更多的事情
版本介绍
jQuery文件下载
压缩 容量更小
未压缩
"""
# jQuery在使用之前 一定要确保已经导入了
# 1 文件下载到了本地 如何解决多个文件反复书写引入语句的代码 可以借助于pycharm自动初始化代码功能完成自动添加（步骤如下） setting Editor file and code template """不想下载jQuery文件 也可以使用""" # 2 直接引入jQuery提供的CDN服务(基于网络直接请求加载) CDN:内容分发网络 CDN有免费的也有收费的 前端免费的cdn网站: bootcdn <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.4.1/jquery.min.js"></script> """你的计算机必须要有网络""" # jQuery基本语法 jQuery(选择器).action() 秉持着jQuery的宗旨 jQuery可简写为 $ jQuery() === $() # jQuery与js代码对比 eg:将p标签内部的文本颜色改为红色 // 原生js代码操作标签 let pEle = document.getElementById(‘d1‘) pEle.style.color = ‘red‘ // jQuery操作标签 $(‘p‘).css(‘color‘,‘blue‘)
// id选择器 $(‘#d1‘) w.fn.init [div#d1]0: div#d1length: 1__proto__: Object(0) // class选择器 $(‘.c1‘) w.fn.init [p.c1, prevObject: w.fn.init(1)]0: p.c1length: 1prevObject: w.fn.init [document]__proto__: Object(0) // 标签选择器 $(‘span‘) w.fn.init(3) [span, span, span, prevObject: w.fn.init(1)] """一定要区分开(重点)""" // jQuery对象如何变成标签对象 undefined $(‘#d1‘)[0] <div id=?"d1">?…?</div>? document.getElementById(‘d1‘) <div id=?"d1">?…?</div>? // 标签对象如何转jQuery对象 undefined $(document.getElementById(‘d1‘)) w.fn.init [div#d1]
$(‘div‘)
w.fn.init(2) [div#d1, div.c1, prevObject: w.fn.init(1)]
$(‘div.c1‘)
w.fn.init [div.c1, prevObject: w.fn.init(1)]0: div.c1length: 1prevObject: w.fn.init [document]__proto__: Object(0)
$(‘div#d1‘)
w.fn.init [div#d1, prevObject: w.fn.init(1)]
$(‘*‘)
w.fn.init(19) [html, head, meta, title, meta, link, script, script, body, span, span, div#d1, span, p#d2, span, span, div.c1, span, span, prevObject: w.fn.init(1)]
$(‘#d1,.c1,p‘) # 并列+混用
w.fn.init(3) [div#d1, p#d2, div.c1, prevObject: w.fn.init(1)]
$(‘div span‘) # 后代
w.fn.init(3) [span, span, span, prevObject: w.fn.init(1)]
$(‘div>span‘) # 儿子
w.fn.init(2) [span, span, prevObject: w.fn.init(1)]
$(‘div+span‘) # 毗邻
w.fn.init [span, prevObject: w.fn.init(1)]
$(‘div~span‘) # 弟弟
w.fn.init(2) [span, span, prevObject: w.fn.init(1)]
$(‘ul li‘)
w.fn.init(10) [li, li, li, li, li, li, li.c1, li, li#d1, li, prevObject: w.fn.init(1)]
$(‘ul li:first‘) # 大儿子
w.fn.init [li, prevObject: w.fn.init(1)]0: lilength: 1prevObject: w.fn.init [document]__proto__: Object(0)
$(‘ul li:last‘) # 小儿子
w.fn.init [li, prevObject: w.fn.init(1)]0: lilength: 1prevObject: w.fn.init [document]__proto__: Object(0)
$(‘ul li:eq(2)‘) # 放索引
w.fn.init [li, prevObject: w.fn.init(1)]0: lilength: 1prevObject: w.fn.init [document]__proto__: Object(0)
$(‘ul li:even‘) # 偶数索引 0包含在内
w.fn.init(5) [li, li, li, li.c1, li#d1, prevObject: w.fn.init(1)]0: li1: li2: li3: li.c14: li#d1length: 5prevObject: w.fn.init [document]__proto__: Object(0)
$(‘ul li:odd‘) # 奇数索引
w.fn.init(5) [li, li, li, li, li, prevObject: w.fn.init(1)]0: li1: li2: li3: li4: lilength: 5prevObject: w.fn.init [document]__proto__: Object(0)
$(‘ul li:gt(2)‘) # 大于索引
w.fn.init(7) [li, li, li, li.c1, li, li#d1, li, prevObject: w.fn.init(1)]0: li1: li2: li3: li.c14: li5: li#d16: lilength: 7prevObject: w.fn.init [document]__proto__: Object(0)
$(‘ul li:lt(2)‘) # 小于索引
w.fn.init(2) [li, li, prevObject: w.fn.init(1)]0: li1: lilength: 2prevObject: w.fn.init [document]__proto__: Object(0)
$(‘ul li:not("#d1")‘) # 移除满足条件的标签
w.fn.init(9) [li, li, li, li, li, li, li.c1, li, li, prevObject: w.fn.init(1)]
$(‘div‘)
w.fn.init(2) [div, div, prevObject: w.fn.init(1)]
$(‘div:has("p")‘) # 选取出包含一个或多个标签在内的标签
w.fn.init [div, prevObject: w.fn.init(1)]
$(‘[username]‘)
w.fn.init(3) [input, input, p, prevObject: w.fn.init(1)]
$(‘[username="jason"]‘)
w.fn.init [input, prevObject: w.fn.init(1)]
$(‘p[username="egon"]‘)
w.fn.init [p, prevObject: w.fn.init(1)]
$(‘[type]‘)
w.fn.init(2) [input, input, prevObject: w.fn.init(1)]
$(‘[type="text"]‘)
w.fn.init(2) [input, input, prevObject: w.fn.init(1)]
$(‘input[type="text"]‘)
w.fn.init [input, prevObject: w.fn.init(1)]0: inputlength: 1prevObject: w.fn.init [document]__proto__: Object(0)
$(‘input[type="password"]‘)
w.fn.init [input, prevObject: w.fn.init(1)]
$(‘:text‘) # 等价于上面第一个
w.fn.init [input, prevObject: w.fn.init(1)]0: inputlength: 1prevObject: w.fn.init [document]__proto__: Object(0)
$(‘:password‘) # 等价于上面第二个
w.fn.init [input, prevObject: w.fn.init(1)]
:text
:password
:file
:radio
:checkbox
:submit
:reset
:button
...
表单对象属性
:enabled
:disabled
:checked
:selected
"""特殊情况"""
$(‘:checked‘) # 它会将checked和selected都拿到
w.fn.init(2) [input, option, prevObject: w.fn.init(1)]0: input1: optionlength: 2prevObject: w.fn.init [document]__proto__: Object(0)
$(‘:selected‘) # 它不会 只拿selected
w.fn.init [option, prevObject: w.fn.init(1)]
$(‘input:checked‘) # 自己加一个限制条件
w.fn.init [input, prevObject: w.fn.init(1)]
$(‘#d1‘).next() # 同级别下一个
w.fn.init [span, prevObject: w.fn.init(1)]0: spanlength: 1prevObject: w.fn.init [span#d1]__proto__: Object(0)
$(‘#d1‘).nextAll()
w.fn.init(5) [span, div#d2, span, span, span.c1, prevObject: w.fn.init(1)]0: span1: div#d22: span3: span4: span.c1length: 5prevObject: w.fn.init [span#d1]__proto__: Object(0)
$(‘#d1‘).nextUntil(‘.c1‘) # 不包括最后一个
w.fn.init(4) [span, div#d2, span, span, prevObject: w.fn.init(1)]0: span1: div#d22: span3: spanlength: 4prevObject: w.fn.init [span#d1]__proto__: Object(0)
$(‘.c1‘).prev() # 上一个
w.fn.init [span, prevObject: w.fn.init(1)]0: spanlength: 1prevObject: w.fn.init [span.c1, prevObject: w.fn.init(1)]__proto__: Object(0)
$(‘.c1‘).prevAll()
w.fn.init(5) [span, span, div#d2, span, span#d1, prevObject: w.fn.init(1)]
$(‘.c1‘).prevUntil(‘#d2‘)
w.fn.init(2) [span, span, prevObject: w.fn.init(1)]
$(‘#d3‘).parent() # 第一级父标签
w.fn.init [p, prevObject: w.fn.init(1)]0: plength: 1prevObject: w.fn.init [span#d3]__proto__: Object(0)
$(‘#d3‘).parent().parent()
w.fn.init [div#d2, prevObject: w.fn.init(1)]
$(‘#d3‘).parent().parent().parent()
w.fn.init [body, prevObject: w.fn.init(1)]
$(‘#d3‘).parent().parent().parent().parent()
w.fn.init [html, prevObject: w.fn.init(1)]
$(‘#d3‘).parent().parent().parent().parent().parent()
w.fn.init [document, prevObject: w.fn.init(1)]
$(‘#d3‘).parent().parent().parent().parent().parent().parent()
w.fn.init [prevObject: w.fn.init(1)]
$(‘#d3‘).parents()
w.fn.init(4) [p, div#d2, body, html, prevObject: w.fn.init(1)]
$(‘#d3‘).parentsUntil(‘body‘)
w.fn.init(2) [p, div#d2, prevObject: w.fn.init(1)]
$(‘#d2‘).children() # 儿子
$(‘#d2‘).siblings() # 同级别上下所有
$(‘div p‘)
# 等价
$(‘div‘).find(‘p‘) # find从某个区域内筛选出想要的标签
"""下述两两等价"""
$(‘div span:first‘)
w.fn.init [span, prevObject: w.fn.init(1)]
$(‘div span‘).first()
w.fn.init [span, prevObject: w.fn.init(3)]0: spanlength: 1prevObject: w.fn.init(3) [span, span#d3, span, prevObject: w.fn.init(1)]__proto__: Object(0)
$(‘div span:last‘)
w.fn.init [span, prevObject: w.fn.init(1)]
$(‘div span‘).last()
w.fn.init [span, prevObject: w.fn.init(3)]
$(‘div span:not("#d3")‘)
w.fn.init(2) [span, span, prevObject: w.fn.init(1)]
$(‘div span‘).not(‘#d3‘)
w.fn.init(2) [span, span, prevObject: w.fn.init(3)]
标签：选择器 eva 偶数 js代码 大于 focus evo file rip
原文地址：https://www.cnblogs.com/BoyGc/p/12918256.html
