Practical application cases of child selector in jQuery

jQuery is a popular library used to simplify Javascript programming. It provides many convenient methods and selectors, one of which is the child selector. The Child selector is used to select the direct child elements of an element, which is very useful when dealing with DOM structures. This article will introduce the usage of the child selector in jQuery in detail through practical application cases, and provide specific code examples.

1. Overview of the Child selector

The Child selector is represented by the ">" symbol in jQuery. It is a relatively precise selector that only selects the direct children of the specified element. elements, rather than grandchild elements and deeper descendant elements. This allows us to target the element more precisely, independent of its descendants.

2. Application case

2.1 Select direct child elements of a specific parent element

Suppose we have the following HTML structure:

<div class="parent">
    <div class="child">子元素1</div>
    <div class="child">子元素2</div>
    <div class="grandchild">孙子元素1</div>
</div>

If we only want to select For div elements with class child directly under the div element with class parent, we can use the Child selector:

$(".parent > .child").css("color", "red");

The above code will select all div elements with class child under the div element with class parent. , and set their text color to red.

2.2 Select direct child elements through the ID of the parent element

Suppose we have the following HTML structure:

<ul id="list">
    <li>第一项
        <ul>
            <li>子项1</li>
            <li>子项2</li>
        </ul>
    </li>
    <li>第二项</li>
</ul>

If we only want to select the direct children of the ul element with the id of list For the li element, we can do this:

$("#list > li").css("font-weight", "bold");

The above code will select all direct child li elements under the ul element with the id of list, and display their text in bold.

2.3 Select the direct child elements of a specific row of the table

Suppose we have the following HTML structure:

<table>
    <tr>
        <td>行1</td>
        <td>行1</td>
    </tr>
    <tr>
        <td>行2</td>
        <td>行2</td>
    </tr>
</table>

If we only want to select the direct child elements td of the first row of the table , we can use the Child selector like this:

$("table > tr:first-child > td").css("background-color", "lightblue");

The above code will select all direct child td elements in the first row of the table and set their background color to light blue.

3. Summary

Through the above practical application cases and code examples, we can see the important role of the Child selector in processing DOM structures. It can help us select target elements more accurately, avoid selecting unnecessary descendant elements, and improve the efficiency and readability of the code. In actual projects, reasonable use of the Child selector will make our Javascript code more concise and easier to maintain.

I hope this article can help readers better understand and apply the Child selector in jQuery and play a greater role in actual projects.

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