Learning the selector of jQuery source code-JS Tutorial-php.cn

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选择器

一、选择器分类

二、选择器API

三、css解析原理

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Learning the selector of jQuery source code

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Jul 09, 2018 pm 03:31 PM

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这篇文章主要介绍了关于jQuery源码之选择器的学习，有着一定的参考价值，现在分享给大家，有需要的朋友可以参考一下

选择器

一、选择器分类

jQuery的选择器和CSS的选择器非常相似

大致可以分为几类：
基本筛选器： eq get first lang It not odd root...
内容筛选器： contains empty has parent...
可见筛选器： hidden visible
子元素筛选器： first-child nth-child only-child...
表单： bottom checkbox foucs input text...

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二、选择器API

id

$('#app')
/* 如果含有特殊字符 */
$('#app\\:ip')  ==> id="app:ip"

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class

$('.class')

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element

$('p')

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*

$('*')
/*匹配全部 */

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selector1,selector2,selector3

$('p,#p,.class,span.love')

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parent selector （祖先和后代的关系）

/* 指定的祖先元素下的所有的后代元素 */
<form>
  <label>Name:</label>
  <input name="name" />
  <fieldset>
      <label>Newsletter:</label>
      <input name="newsletter" />
 </fieldset>
</form>
<input name="none" />

$('form input')
/* result */
/* [ <input name="name" />, <input name="newsletter" /> ] */

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parent > child （父亲和儿子的关系）

/* 匹配父元素下的所有的子元素 */
<form>
  <label>Name:</label>
  <input name="name" />
  <fieldset>
      <label>Newsletter:</label>
      <input name="newsletter" />
 </fieldset>
</form>
<input name="none" />

$('form > input')

/* result */
/* [ <input name="name" /> ] */

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prev + next （下一个兄弟关系）

/* 匹配所有跟在prev后面的下一个元素 */
<form>
  <label>Name:</label>
  <input name="name" />
  <fieldset>
      <label>Newsletter:</label>
      <input name="newsletter" />
 </fieldset>
</form>
<input name="none" />


$('label + input')

/* result */
/* [ <input name="name" />, <input name="newsletter" /> ] */

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prev ~ siblings (下面的所有兄弟元素)

/* 匹配prev后面的所有的兄弟元素 */
<form>
  <label id="name">Name:</label>
  <input name="name" />
  <fieldset>
      <label>Newsletter:</label>
      <input name="newsletter" />
 </fieldset>
 <input name="none" />
 <input name="sex" />
</form>


$('#name ~ input')
/* result */
/* <input name="name" />
<input name="none" />
<input name="sex" /> */

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:first

获取匹配的第一个元素

$('input:first')
$('ul li:first');

// 捕获到同类型元素后，在取其第一个

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:not(selector)

去除选定的selector那部分

// 去除已选择的元素中的部分
$('input:not(:checked)')

<input name="apple" />
<input name="flower" checked="checked" />
// result
// [ <input name="apple" /> ]

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:even(index)

// 匹配索引为偶数的，从 0 开始计数（将0包含进even）
// 第 1，3，5，7 行
//

$('tr:even')

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:odd(index)

// 匹配索引为奇数的
// 第2，4，6，8 行

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:eq(index)

// 匹配给定一个索引

$('tr:eq(1)')

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:gt(index)

// 匹配大于索引值的项
$('tr:gt(1)')

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:lang(language) 1.9+

// 匹配指定语言的元素
$('p:lang(en)')
// 选择器$("p:lang(en)")将匹配<p lang="en"> and <p lang="en-us">（和他们的后代<p>），但不包括<p lang="fr">

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:last

// 获取匹配的最后个元素
$('p:last')

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:lt(index)

// 匹配索引小于指定值
//
$('p:lt(4)')

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:header

// 匹配所有的标题元素
// h1 h2 h3 h4 h5 h6
$(":header").css("background", "#EEE");

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:animated

// 匹配所有正在执行动画的元素
<button id="run">Run</button><p></p>

$('p:not(:animated)').animate({
  left: '+=20px'
},1000);

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:focus 1.6+

// 匹配当前获取焦点的元素。
$('input:focus').css("background":"#ccc");

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:root 1.9+

// 匹配页面的根元素
$(':root').css("background":"yellow");
// 设置<html>背景颜色为黄色

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:target 1.9+

// 如果url中包含有http://example.com/#foo
$('a:target')
// 就是选中了 <a id="foo"></a>

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:contains(text)

// 匹配包含给定文本的
$('p:contains('join')');

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:empty()

$('p:empty')
// 匹配不包含子元素或文本内容
<table>
  <tr><td>Value 1</td><td></td></tr>
  <tr><td>Value 2</td><td></td></tr>
</table>

$('td:empty')
// [ <td></td>, <td></td> ]

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:has()

// 匹配含有has内部选择器选中的元素的元素
$('p:has('p')')

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:parent 与empty相反

// 匹配含有子元素或者文本内容的
$('td:parent')
<table>
  <tr><td>Value 1</td><td></td></tr>
  <tr><td>Value 2</td><td></td></tr>
</table>

// <td>Value 1</td><td>Value 2</td>

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:hidden

// 匹配不可见的元素
//
$('input:hidden')

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:visable

// 匹配可见的元素
<table>
  <tr style="display:none"><td>Value 1</td></tr>
  <tr><td>Value 2</td></tr>
</table>

$('tr:visable')
//  <tr><td>Value 2</td></tr> ]

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[attribute]

// 匹配包含给定属性的元素
$('input[name]')

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[attribute=value]

// 匹配给定的属性是某个特定值的元素
$('input[name="sex"]')

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[attribute!=value]

[attribute^=vlaue]

// 匹配属性以value开头

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[attribute$=value]

// 匹配属性以value结尾

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[attribute*=value]

// 匹配属性包含某些值的元素

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selector1[selector3]

// 匹配同时满足多个属性选择器的元素
$("input[id][name$='man']")

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:first-child

// 匹配所给选择器( :之前的选择器)的第一个子元素，最终的结果可能是多个，不同于:first 之处是，:first是指匹配到的元素（：之前的元素）的第一个。

<ul>
  <li>John</li>
  <li>Karl</li>
  <li>Brandon</li>
</ul>
<ul>
  <li>Glen</li>
  <li>Tane</li>
  <li>Ralph</li>
</ul>

$('ul li:first-child');
// [ <li>John</li>, <li>Glen</li> ]

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:first-of-type

// [1]
$('span:first-of-type')
// 匹配到span元素，而且这个span元素是其父级的第一个span

<p id="n1">
    <p id="n2" class="abc">
        <label id="n3">label1</label>
        <span id="n4">span1</span>
        <span id="n5" class="abc">span2</span>
        <span id="n6">span3</span>
    </p>
    <p id="n7">
        <span id="n8" class="abc">span1</span>
        <span id="n9">span2</span>
    </p>
</p>

// <span id="n4">span1</span>  <span id="n8" class="abc">span1</span>

// 【2】
$('.abc:first-of-type')
<p id="n1">
    <p id="n2" class="abc">
        <label id="n3">label1</label>
        <span id="n4">span1</span>
        <span id="n5" class="abc">span2</span>
        <span id="n6">span3</span>
    </p>
    <p id="n7">
        <span id="n8" class="abc">span1</span>
        <span id="n9">span2</span>
    </p>
</p>

// <p id="n2" class="abc"></p>    <span id="n8" class="abc">span1</span>

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:last-child

同理:first-child

:last-of-type

:nth-child(n)

n可以是：
序号、even、odd、（3n+2）
(3n+2)表示从第二个开始，匹配3的倍数的元素

// 这里的n是从1 开始的，跟:first-child类似
<ul>
  <li>John</li>
  <li>Karl</li>
  <li>Brandon</li>
</ul>
<ul>
  <li>Glen</li>
  <li>Tane</li>
  <li>Ralph</li>
</ul>

$('ul li:nth-child(2)')
// <li>Karl</li><li>Tane</li>

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:nth-last-child(n)

n可以是：
序号、even、odd、（3n+2）
(3n+2)表示从第二个开始，匹配3的倍数的元素

跟:nth-child(n) 类似，只是它是从后往前算的

only-child

// 如果某个元素是父元素中唯一的子元素，那将会被匹配
<ul>
  <li>John</li>
  <li>Karl</li>
  <li>Brandon</li>
</ul>
<ul>
  <li>Glen</li>
</ul>

$('ul li:only-child')
// <li>Glen</li>

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:input

匹配所有 input, textarea, select 和 button 元素

<form>
    <input type="button" value="Input Button"/>
    <input type="checkbox" />

    <input type="file" />
    <input type="hidden" />
    <input type="image" />

    <input type="password" />
    <input type="radio" />
    <input type="reset" />

    <input type="submit" />
    <input type="text" />
    <select><option>Option</option></select>

    <textarea></textarea>
    <button>Button</button>

</form>
// 全选$(':input')

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:text

<form>
  <input type="text" />
  <input type="checkbox" />
  <input type="radio" />
  <input type="image" />
  <input type="file" />
  <input type="submit" />
  <input type="reset" />
  <input type="password" />
  <input type="button" />
  <select><option/></select>
  <textarea></textarea>
  <button></button>
</form>

$(':text')
// <input type="text" />

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:password

<form>
  <input type="text" />
  <input type="checkbox" />
  <input type="radio" />
  <input type="image" />
  <input type="file" />
  <input type="submit" />
  <input type="reset" />
  <input type="password" />
  <input type="button" />
  <select><option/></select>
  <textarea></textarea>
  <button></button>
</form>

$(':password')
// <input type="password" />

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:radio

<form>
  <input type="text" />
  <input type="checkbox" />
  <input type="radio" />
  <input type="image" />
  <input type="file" />
  <input type="submit" />
  <input type="reset" />
  <input type="password" />
  <input type="button" />
  <select><option/></select>
  <textarea></textarea>
  <button></button>
</form>

$(':radio')
// <input type="radio" />

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:submit

<form>
  <input type="text" />
  <input type="checkbox" />
  <input type="radio" />
  <input type="image" />
  <input type="file" />
  <input type="submit" />
  <input type="reset" />
  <input type="password" />
  <input type="button" />
  <select><option/></select>
  <textarea></textarea>
  <button></button>
</form>

$(':submit')
// <input type="submit" />

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:image

<form>
  <input type="text" />
  <input type="checkbox" />
  <input type="radio" />
  <input type="image" />
  <input type="file" />
  <input type="submit" />
  <input type="reset" />
  <input type="password" />
  <input type="button" />
  <select><option/></select>
  <textarea></textarea>
  <button></button>
</form>

$(':image')
// <input type="image" />

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:reset
:button

:file

:enabled

选择可用的元素

<form>
  <input name="email" disabled="disabled" />
  <input name="id" />
</form>

$("input:enabled")
// <input name="id" />

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:disabled

选择不能使用的

:checked

$("input:checked")

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:selected

$('option:selected')

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三、css解析原理

以上就是本文的全部内容，希望对大家的学习有所帮助，更多相关内容请关注PHP中文网！

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Learning the selector of jQuery source code

选择器

一、选择器分类

二、选择器API

三、css解析原理

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