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Umfassende Erklärung des Jquery-Selektors

零下一度
零下一度Original
2017-07-19 16:56:401178Durchsuche

1 Übersicht

Wir haben die jQuery-Auswahlfunktion mit einem einfachen CSS-Selektor verwendet: $( ). Jetzt ist es an der Zeit, sich mit der jQuery-Selektorsyntax und einigen Methoden zum Extrahieren und Erweitern des Satzes ausgewählter Elemente zu befassen.

1. jQuery-Selektor

In der durch den CSS3-Selektor-Standardentwurf definierten Selektorsyntax unterstützt jQuery einen ziemlich vollständigen Satz von Teilmengen und fügt auch einige nicht standardmäßige, aber nützliche Teilmengen hinzu. Klasse. Hinweis: In diesem Abschnitt geht es um jQuery-Selektoren. Viele dieser Selektoren (aber nicht alle) können in CSS-Stylesheets verwendet werden. Die Selektorsyntax hat eine dreistufige Struktur. Sie haben zweifellos Selektoren in ihrer einfachsten Form gesehen. „#te st“ wählt das Element mit dem ID-Attribut „test“ aus. „blockquote“ wählt alle

-Elemente im Dokument aus, während „div.note“ alle
-Elemente auswählt. Einfache Selektoren können zu „kombinierten Selektoren“ wie „div.note>p“ und „blockquote i“ kombiniert werden, sofern die kombinierenden Zeichen als Trennzeichen verwendet werden. Einfache und kombinierte Selektoren können auch in durch Kommas getrennte Listen gruppiert werden. Diese Art von Selektorgruppe ist die häufigste Form der Auswahl, die an die Funktion $() übergeben wird. Bevor wir kombinierte Selektoren und Selektorgruppen erklären, müssen wir zunächst die Syntax einfacher Selektoren verstehen.


2 Basisauswahl

2.1 Liste

2.2 Beispielcode

(1) ID-Selektor

Setzen Sie die Hintergrundfarbe des Elements mit der ID Nachname auf Blau

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("#lastname").css("background-color", "#0000ff");11            12         });13 14     </script>15 </head>16 <body>17     <div id="lastname">id为lastname的选择器</div>18 </body>19 </html>
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(2) Klassenauswahl

Setzen Sie die Hintergrundfarbe des Intro-Elements auf Blau

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $(".intro").css("background-color", "#0000ff");11            12         });13 14     </script>15 </head>16 <body>17     <div class="intro">div选择器测试</div>18     <p class="intro">p测试选择器</p>19 </body>20 </html>
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(3) Elementauswahl

Setzen Sie die Hintergrundfarbe des p-Elements auf Blau

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("p").css("background-color", "#0000ff");11            12         });13 14     </script>15 </head>16 <body>17      <p>p测试选择器</p>18 </body>19 </html>
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(4) Alle Selektoren

Alle Elemente unter dem Körper durchlaufen und ihre Hintergrundfarbe auf Blau setzen

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("body *").css("background-color", "#0000ff");11            12         });13 14     </script>15 </head>16 <body>17     <div>选择器测试</div>18     <p>p元素</p>19 </body>20 </html>
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(5)并列选择器

 将元素p和元素div背景色设置为蓝色

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("p,div").css("background-color", "#0000ff");11            12         });13 14     </script>15 </head>16 <body>17     <div>选择器测试</div>18     <p>p元素</p>19 </body>20 </html>
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3   层次选择器

3.1 一览表

3.2 示例代码

(1)parent>child(直系子元素,即直接下一代元素)

设置div元素的第一代元素为span的元素的背景色为蓝色

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("div>span").css("background-color", "#0000ff");11            12         });13 14     </script>15 </head>16 <body>17     <div>18         <span>DOM树,DIV第一代</span>19         <p>20             <span>DOM树,第二代</span>21         </p>22         <span>DOM树,DIV第一代</span>23     </div>24 </body>25 </html>
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测试结果:

结果分析:根据如上代码画出的DOM树如下,可以很清晰看出,DIV有三个直接孩子,即第一代span,p,span,代码中div>span,表示div下的直接第一代span,因此,测试结果就不难理解了。

(2)prev+next(prev元素的下一个兄弟元素,等同于next()方法)

设置类为intro元素的下一个兄弟元素背景色为蓝色

 1  <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $(".intro+div").css("background-color", "#0000ff");11             //$(".intro").next("div").css("background-color", "#0000ff");12            13         });14 15     </script>16 </head>17 <body>18     <div>1</div>19     <p class="intro">2</p>20     <div>3</div>21     <div>4</div>22     <span class="item">5</span>23     <div>6</div>24 </body>25 </html>
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测试结果:

结果分析:根据如上代码画出DOM树如下图,测试结果显而易见。

(3)prev~siblings(prev元素的所有兄弟元素,等同于nextAll()方法)

 设置类为intro元素之后的所有兄弟元素为div元素的背景色为蓝色

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $(".intro~div").css("background-color", "#0000ff");11         });12 13     </script>14 </head>15 <body>16     <div>G0</div>17     <div class="intro">G1</div>18     <div>G2</div>19     <span>G3</span>20     <div>G4</div>21 </body>22 </html>
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测试结果:

分析测试结果:根据如上代码画出DOM树如下图,测试结果显而易见。

4   过滤选择器

4.1 基本过滤选择器

4.1.1  一览表

4.1.2  代码示例

(1):first(选取第一个元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("span:first").css("background-color", "#0000ff");11         });12 13     </script>14 </head>15 <body>16     <span>G1</span>17     <span>G2</span>18     <span>G3</span>19 </body>20 </html>
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测试结果:

(2):last(选取最后一个元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("span:last").css("background-color", "#0000ff");11         });12 13     </script>14 </head>15 <body>16     <span>G1</span>17     <span>G2</span>18     <span>G3</span>19 </body>20 </html>
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测试结果:

(3):not(取非元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("div:not(.wrap)").css("background-color", "#0000ff");11         });12 13     </script>14 </head>15 <body>16     <div>G1</div>17     <div class="wrap">G2</div>18 </body>19 </html>
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但是,请注意下面的代码:当G1所在div和G2所在div是父子关系时,G1和G2都会变色。

1 <div>2     G1    <div class="wrap">G2</div>3 </div>
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(4):even(索引为偶数,索引 index从0开始)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("div:even").css("background-color", "#0000ff");11         });12 13     </script>14 </head>15 <body>16     <div>G1</div>17     <div>G2</div>18     <div>G3</div>19     <div>G4</div>20 </body>21 </html>
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测试结果:

(5):odd(索引为奇数,索引 index从0开始)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("div:odd").css("background-color", "#0000ff");11         });12 13     </script>14 </head>15 <body>16     <div>G1</div>17     <div>G2</div>18     <div>G3</div>19     <div>G4</div>20 </body>21 </html>
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测试结果:

(6):eq(x)(取指定索引的元素,x为从0开始的索引)

设置索引为2的div元素背景为蓝色

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("div:eq(2)").css("background-color", "#0000ff");11         });12 13     </script>14 </head>15 <body>16     <div>G1</div>17     <div>G2</div>18     <div>G3</div>19     <div>G4</div>20 </body>21 </html>
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测试结果:

(7):lt(x))(取小于指定索引的元素,x为从0开始的索引)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("div:lt(2)").css("background-color", "#0000ff");11         });12 13     </script>14 </head>15 <body>16     <div>G1</div>17     <div>G2</div>18     <div>G3</div>19     <div>G4</div>20 </body>21 </html>
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测试结果:

(8):gt(x))(取大于指定索引的元素,x为从0开始的索引)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("div:gt(2)").css("background-color", "#0000ff");11         });12 13     </script>14 </head>15 <body>16     <div>G1</div>17     <div>G2</div>18     <div>G3</div>19     <div>G4</div>20 </body>21 </html>
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测试结果:

(8):header(取h1-h6标题元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $(":header").css("background-color", "#0000ff");11         });12 13     </script>14 </head>15 <body>16     <h1>测试H1标题</h1>17     <div>G1</div>18     <div>G2</div>19     <div>G3</div>20     <h2>测试h2标题</h2>21     <h3>测试h3标题</h3>22     <h4>测试h4标题</h4>23     <div>G4</div>24     <h5>测试h5标题</h5>25     <h6>测试h6标题</h6>26 </body>27 </html>
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测试结果:

(9):animated(所有动画元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9          $(document).ready(function () {10             function aniDiv() {11                 $("#box").animate({ width: 300 }, "slow");12                 $("#box").animate({ width: 100 }, "slow", aniDiv);13             }14             aniDiv();15             $(".btn1").click(function () {16                 $(":animated").css("background-color", "#0000ff");17             });18         });19 20     </script>21     <style>22         div {23                 background: #98bf21;24                 height: 40px;25                 width: 100px;26                 position: relative;27                 margin-bottom: 5px;28              }29     </style>30 </head>31 <body>32     <div></div>33     <div id="box"></div>34     <div></div>35     <button class="btn1">Mark animated element</button>36 </body>37 </html>
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测试结果:

 

4.2 内容过滤选择器

4.2.1 一览表

4.2.2 示例代码

(1):contains(text)(取包含text文本的元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9          $(document).ready(function () {10              $('div:contains("G2")').css("background-color", "#0000ff");11          });12 13     </script>14     15 </head>16 <body>17     <div>G1</div>18     <div>G2</div>19     <div>G3</div>20 </body>21 </html>
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测试结果:

(2):empty(取不包含子元素或文本为空的元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9          $(document).ready(function () {10              $('div:empty').html('没有内容');11          });12 13     </script>14     15 </head>16 <body>17     <div>G1</div>18     <div>G2</div>19     <div>G3</div>20     <div></div>21 </body>22 </html>
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测试结果:

(3) :has(selector)(取选择器匹配的元素)

即使span不是div的直系子元素,也会生效

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             // 为包含span元素的div添加边框11             $('div:has(span)').css('border', '1px solid #000');12         });13 14     </script>15     16 </head>17 <body>18     <div>19         <h2>20             A     <span>B</span>21         </h2>22     </div>23 </body>24 </html>
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测试结果:

(4):parent(取包含子元素或文本的元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $('ol li:parent').css('border', '1px solid #000');11         });12 13     </script>14     15 </head>16 <body>17     <ol>18         <li></li>19         <li>A</li>20         <li></li>21         <li>D</li>22     </ol>23 </body>24 </html>
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测试结果:

4.3 可见性过滤选择器

4.3.1 一览表

4.3.2 示例代码

(1):hidden(取不可见的元素)

匹配display:none,,visibility:hidden,capacity:0元素

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $('div:hidden').show(500);11             alert($('input:hidden').val());12         });13     </script>14     <style type="text/css">15             div         
16             {17                 margin: 10px;18                 width: 200px;19                 height: 40px;20                 border: 1px solid #FF0000;21                 display:block;22              }23 24             .hid-1         
25             {26                 display: none;27              }28 29             .hid-2         
30             {31                 visibility: hidden;32             }33         34     </style>35 </head>36 <body>37     <div class="hid-1">display: none</div>38     <div class="hid-2">visibility: hidden</div>39     <input type="hidden" value="hello" />40 </body>41 </html>
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测试结果:

(2):visible(取可见的元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9          $(document).ready(function () {10              $('div:visible').css("background-color", "#0000ff");11          });12 13     </script>14     15 </head>16 <body>17     <div style="display:none">G1</div>18     <div>G2</div>19     <div style="display:none">G3</div>20     <div>G4</div>21 22 </body>23 </html>24 25 26
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测试结果:

4.4 属性过滤选择器

4.4.1 一览表

4.4.2 代码示例

(1)[attribute](取拥有attribute属性的元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9          $(document).ready(function () {10              $('div[class]').css("background-color", "#0000ff");11          });12 13     </script>14     15 </head>16 <body>17     <div>G1</div>18     <div>G2</div>19     <div>G3</div>20     <div class="div4">G4</div>21 22 </body>23 </html>24 25 26
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测试结果:

(2)[attribute = value](取attribute属性值等于value)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9          $(document).ready(function () {10              $('div[class=div3]').css("background-color", "#0000ff");11          });12 13     </script>14     15 </head>16 <body>17     <div>G1</div>18     <div>G2</div>19     <div class="div3">G3</div>20     <div class="div4">G4</div>21 22 </body>23 </html>24 25 26
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测试结果:

(3) [attribute != value](取attribute属性值不等于value的元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9          $(document).ready(function () {10              $('div[class!=div3]').css("background-color", "#0000ff");11          });12 13     </script>14     15 </head>16 <body>17     <div>G1</div>18     <div>G2</div>19     <div class="div3">G3</div>20     <div class="div4">G4</div>21 22 </body>23 </html>24 25 26
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测试结果:

(4)[attribute $= value](attribute属性值以value结束)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9          $(document).ready(function () {10              $('[id$=div]').css("background-color", "#0000ff");11          });12 13     </script>14     15 </head>16 <body>17     <div id="first_div">G1</div>18     <div id="second_div">G2</div>19     <div class="div3" title="3div">G3</div>20     <div class="div4">G4</div>21 22 </body>23 </html>
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测试结果:

(5))[attribute^= value](attribute属性值以value开始)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9          $(document).ready(function () {10              $('[id^=first]').css("background-color", "#0000ff");11          });12 13     </script>14     15 </head>16 <body>17     <div id="first_div">G1</div>18     <div id="second_div">G2</div>19     <div class="div3" title="3div">G3</div>20     <div class="div4">G4</div>21 22 </body>23 </html>24 25 26
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测试结果:

(6)[attribute *= value](attribute属性值包含value值)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9          $(document).ready(function () {10              $('[id*=first]').css("background-color", "#0000ff");11          });12 13     </script>14     15 </head>16 <body>17     <div id="first_div">G1</div>18     <div id="second_div">G2</div>19     <div class="div3" title="3div">G3</div>20     <div class="div4">G4</div>21 22 </body>23 </html>
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测试结果:

注释:在属性选择器中,^$符号和正则表达式的开始结束符号表示的含义是一致的,*模糊匹配,类似于sql中的like '%str%'。

(7)[selector1][selector2](复合型属性过滤器,同时满足多个条件)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9          $(document).ready(function () {10              $('div[class=div3][title=3div]').css("background-color", "#0000ff");11          });12 13     </script>14     15 </head>16 <body>17     <div>G1</div>18     <div>G2</div>19     <div class="div3" title="3div">G3</div>20     <div class="div4">G4</div>21 22 </body>23 </html>24 25 26
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测试结果:

4.5 子元素过滤选择器

4.5.1 一览表

4.5.2 代码示例

(1)first-child(表示匹配的第一个元素)和last-child(表示匹配的最后一个子元素)

 需要大家注意的是,:fisrst和:last返回的都是单个元素,而:first-child和:last-child返回的都是集合元素。举个 例子:div:first返回的是整个DOM文档中第一个div元素,而div:first-child是返回所有div元素下的第一个元素合并后的集 合。

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("div:first-child").css("background-color", "#B2E0FF");11             $("div:last-child").css("background-color", "red");12         });13     </script>14 </head>15 <body>16      <div>17          <div>1</div>18          <div>2</div>19          <p>3</p>20      </div>21     <div>4</div>22     <div>last</div>23 </body>24 </html>
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测试结果:

(3)only-child(当某个元素有且仅有一个子元素时,:only-child才会生效)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $("div:only-child").css("background-color", "red");11          });12     </script>13 </head>14 <body>15      <div>16          <div>1</div>17          <div>2</div>18          <p>3</p>19      </div>20     <div>4</div>21     <div>last22     <div>ddd</div>23     </div>24 </body>25 </html>
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测试结果:

(4)nth-child

看到这个就想起英文单词里的,fourth, fifth, sixth……,nth表示第n个,:nth-child就表示第n个child元素。要注意的是,这儿的n不像eq(x)、gt(x)或lt(x)是从 0开始的,它是从1开始的,英文里好像也没有zeroth这样的序号词吧。

:nth-child有三种用法:

1) :nth-child(x),获取第x个子元素
2) :nth-child(even)和:nth-child(odd),从1开始,获取第偶数个元素或第奇数个元素
3) :nth-child(xn+y),x>=0,y>=0。例如x = 3, y = 0时就是3n,表示取第3n个元素(n>=0)。实际上xn+y是上面两种的通项式。(当x=0,y>=0时,等同于:hth- child(x);当x=2,y=0时,等同于nth-child(even);当x=2,y=1时,等同于:nth-child(odd))

4.6 表单对象属性过滤选择器

4.6.1 一览表

4.6.2 代码示例

(1):enabled和:disabled(取可用或不可用元素)

:enabled和:diabled的匹配范围包括input, select, textarea

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $(':enabled').css('border', '1px solid #FF0000');11             $(':disabled').css('border', '1px solid #0000FF');12         });13 14     </script>15     16 </head>17 <body>18     <div>19         <input type="text" value="可用的文本框" />20     </div>21     <div>22         <input type="text" disabled="disabled" value="不可用的文本框" />23     </div>24     <div>25         <textarea disabled="disabled">不可用的文本域</textarea>26     </div>27     <div>28         <select disabled="disabled">29             <option>English</option>30             <option>简体中文</option>31         </select>32     </div>33 </body>34 </html>
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测试结果:

(2):checked(取选中的单选框或复选框元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $(".btn1").click(function () {11                 $(":checked").hide();12             });13         });14     </script>15     16 </head>17 <body>18     <input type="radio" name="sex" value="male" checked="checked" /> Male19     <br />20     <input type="radio" name="sex" value="female" /> Female21     <br />22     I have a bike:23     <input type="checkbox" name="vehicle" value="Bike" />24     <br />25     I have a car:26     <input type="checkbox" name="vehicle" value="Car" checked="checked" />27     <br />28     I have an airplane:29     <input type="checkbox" name="vehicle" value="Airplane" />30     <button class="btn1">Hide Checked Options</button>31 32 </body>33 </html>
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(3):selected(取下拉列表被选中的元素)

 1 <html> 2 <head> 3 <script type="text/javascript" src="/jquery/jquery.js"></script> 4 <script type="text/javascript"> 5 $(document).ready(function(){ 6   $(".btn1").click(function(){ 7     $(":selected").hide(); 8   }); 9 });10 </script>11 </head>12 <body>13 14 <select multiple="multiple">15   <option>Volvo</option>16   <option selected="selected">Saab</option>17   <option>Mercedes</option>18   <option>Audi</option>19 </select>20 <br />21 <button class="btn1">Hide Selected</button>22 </body>23 </html>
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5   表单选择器

5.1 一览表

5.2 测试代码

(1):input()(选择所有input元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $(":input").css("background-color", "#B2E0FF");11         });12     </script>13 </head>14 <body>15     <form action="">16         Name: <input type="text" name="user" />17         <br />18         Password: <input type="password" name="password" />19         <br />20         <button type="button">Useless Button</button>21         <input type="button" value="Another useless button" />22         <br />23         <input type="reset" value="Reset" />24         <input type="submit" value="Submit" />25         <br />26     </form>27 </body>28 </html>
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测试结果:

(2):text(选取所有text元素)

 1 <!DOCTYPE html> 2  3 <html> 4 <head> 5     <meta name="viewport" content="width=device-width" /> 6     <script src="~/Scripts/jquery-1.10.2.js"></script> 7     <title>JQuery函数</title> 8     <script type="text/javascript"> 9         $(document).ready(function () {10             $(":text").css("background-color", "#B2E0FF");11         });12     </script>13 </head>14 <body>15     <form action="">16         Name: <input type="text" name="user" />17         <br />18         Password: <input type="password" name="password" />19         <br />20         <button type="button">Useless Button</button>21         <input type="button" value="Another useless button" />22         <br />23         <input type="reset" value="Reset" />24         <input type="submit" value="Submit" />25         <br />26     </form>27 </body>28 </html>
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测试结果:

(3):select和:button

(4)其他表单元素比较简单,在此不列举。

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