Summary examples of first-child, nth-child, and last-child selectors in jQuery

Last Update:2017-01-17 Source: Internet

Author: User

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In jQuery: example of first-child selector usage

This selector can match the first child element of the parent element.

Syntax structure:

$ (": First-child ")

This selector should also be used with other selectors, such as class selector and element selector. For example:

$ ("Ul li: first-child" ).css ("color", "blue ")

The above code sets the font color of the first li element under the parent element to blue.

Note: it is necessary to combine the above code to describe the concept. The parent element mentioned here is not li, but the parent element of li. Many people often mistakenly think that it is the last element in the child element that matches the li element.

Instance code:

The code is as follows:

Copy code

<! Doctype html>
<Html>
<Head>
<Meta http-equiv = "Content-Type" content = "text/html; charset = utf-8">
<Meta name = "author" content = "http://www.jb51.net/"/>
<Title>: first-child selector-Yunqi Community </title>
<Script type = "text/javascript" src = "mytest/jQuery/jquery-1.8.3.js"> </script>
<Script type = "text/javascript">
$ (Document). ready (function (){
$ ("Button"). click (function (){
$ ("Ul li: first-child" ).css ("color", "blue ")
})
})
</Script>
</Head>
<Body>
<Div>
<Ul>
<Li class = "houtai" title = "asp"> ASP tutorial </li>
<Li class = "houtai" title = "net"> ASP. NET Tutorial </li>
<Li class = "houtai" title = "php"> PHP Tutorial </li>
</Ul>
<Ul>
<Li class = "qiantai" title = "html"> html tutorial </li>
<Li class = "qiantai" title = "div"> DIV + CSS tutorial </li>
<Li class = "qiantai" title = "jquery"> jQUERY tutorial </li>
<Li class = "qiantai" title = "js"> jAVAScript tutorial </li>
</Ul>
</Div>
<Button> Click to view results </button>
</Body>
</Html>

In the above code, click the button to set the text color of the first li element under every ul to blue.

Example of nth-child selector usage in jQuery

This selector matches the nth child or parity element under its parent element.
The: eq (index) selector matches only one element, while the nth-child selector matches child elements for each parent element.
: Nth-child starts from 1, while: eq () starts from 0.
Syntax structure:

$ (": Nth-child ")

This selector should also be used with other selectors, such as class selector and element selector. For example:

$ ("Li: nth-child (2)" ).css ("color", "blue ")

The above code sets the font color of the second li element under the parent element to blue. You can also calculate the parity child element of the parent element. For example:

$ ("Li: nth-child (even)" ).css ("color", "blue ")

The code above can set the font color of the li element in the order of an even number under the parent element to blue.

Note: it is necessary to combine the above code to describe the concept. The parent element mentioned here is not li, but the parent element of li.
Many people often mistakenly think that it is the last element in the child element that matches the li element.

Instance code:

The code is as follows:

Copy code

<! DOCTYPE html>
<Html>
<Head>
<Meta charset = "utf-8">
<Meta name = "author" content = "http://www.jb51.net/"/>
<Title>: nth-child selector-Yunqi Community </title>
<Script type = "text/javascript" src = "mytest/jQuery/jquery-1.8.3.js"> </script>
<Script type = "text/javascript">
$ (Document). ready (function (){
$ ("Button"). click (function (){
$ ("Li: nth-child (2)" ).css ("color", "blue ")
})
})
</Script>
</Head>
<Body>
<Div>
<Ul>
<Li class = "houtai" title = "asp"> ASP tutorial </li>
<Li class = "houtai" title = "net"> ASP. NET Tutorial </li>
<Li class = "houtai" title = "php">; PHP Tutorial </li>
</Ul>
<Ul>
<Li class = "qiantai" title = "html"> html tutorial </li>
<Li class = "qiantai" title = "div"> DIV + CSS tutorial </li>
<Li class = "qiantai" title = "jquery"> jQUERY tutorial </li>
<Li class = "qiantai" title = "js"> jAVAScript tutorial </li>
</Ul>
</Div>
<Button> Click to view results </button>
</Body>
</Html>

Examples of last-child selector usage in jQuery

This selector can match the last child element of the parent element.

Note: only one element is selected for last, and this selector matches the last child element of each parent element.
Syntax structure:

$ (": Last-child ")

This selector should also be used with other selectors, such as class selector and element selector. For example:

$ ("Li: last-child" ).css ("color", "blue ")

The above code sets the font color of the last li element under the parent element to blue.

Note: it is necessary to combine the above code to describe the concept. The parent element mentioned here is not li, but the parent element of li. Many people often mistakenly think that it is the last element in the child element that matches the li element.

Instance code:

The code is as follows:

Copy code

<! DOCTYPE html>
<Html>
<Head>
<Meta charset = "utf-8">
<Meta name = "author" content = "http://www.jb51.net/"/>
<Title> Yunqi Community </title>
<Script type = "text/javascript" src = "mytest/jQuery/jquery-1.8.3.js"> </script>
<Script type = "text/javascript">
$ (Document). ready (function (){
$ ("Button"). click (function (){
$ ("Li: last-child" ).css ("color", "blue ")
})
})
</Script>
</Head>
<Body>
<Div>
<Ul>
<Li class = "houtai" title = "asp"> ASP tutorial </li>
<Li class = "houtai" title = "net"> ASP. NET Tutorial </li>
<Li class = "houtai" title = "php"> PHP Tutorial </li>
</Ul>
<Ul>
<Li class = "qiantai" title = "html"> html tutorial </li>
<Li class = "qiantai" title = "div"> DIV + CSS tutorial </li>
<Li class = "qiantai" title = "jquery"> jQUERY tutorial </li>
<Li class = "qiantai" title = "js"> jAVAScript tutorial </li>
</Ul>
</Div>
<Button> Click to view results </button>
</Body>
</Html>

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

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