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Let's talk about how to use jQuery

PHPz

Release： 2023-04-06 11:09:20

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jQuery is a lightweight JavaScript library that greatly simplifies the work of developers and makes it more convenient to process DOM, events, animations and other operations. This article will introduce how to use jQuery to help beginners get started faster.

1. Why use jQuery

Before introducing how to use jQuery, let’s first understand its importance. Using jQuery can greatly simplify the JavaScript writing process, allowing developers to focus more on the implementation of page interaction without having to worry too much about the underlying implementation of JavaScript. In addition, jQuery is also cross-browser compatible, allowing the page to achieve better performance and user experience.

2. How to use jQuery

Download jQuery

First of all, to use jQuery, you need to introduce the JavaScript file where jQuery is located in the page. From the jQuery official website http://jquery.com/, you can download different versions of jQuery library files, including uncompressed versions and compressed versions. The uncompressed version includes comments and spaces for development and debugging, while the compressed version These are not included for release to production. After downloading, save the jQuery file to the project, and then introduce the file into the page.

Grammar structure

The syntax structure of jQuery is similar to the CSS selector. You select elements on the page through the selector, and then add or delete styles, attributes, events etc. The following is a simple example:

<html>
<head>
    <script src="jquery.min.js"></script>
    <script>
        $(document).ready(function(){
            $("button").click(function(){
                $("p").hide();
            });
        });
    </script>
</head>
<body>

<button>隐藏段落</button>

<p>这是一个段落。</p>
<p>这是另一个段落。</p>

</body>
</html>

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In the above code, the JavaScript code in the page is delayed until the page DOM tree is loaded through the $(document).ready() method. implement. Then, through the $("button").click() method and the $("p").hide() method, set the click event response function of the button and change the page All  elements are hidden.

Common methods

In addition to selectors and event methods, jQuery also provides a large number of common methods for operating the Document Object Model (DOM), animation effects, Ajax etc.

(1) Manipulating DOM

jQuery provides a large number of DOM operation methods for adding, deleting, modifying, and checking the content, attributes, styles, etc. in page elements. The following are some commonly used jQuery DOM manipulation methods:

.html()Method: Get or set the content of the selected element.
.text()Method: Get or set the text content of the selected element.
.attr()Method: Get or set the attribute value of the selected element.
.addClass()Method: Add one or more classes to the selected element.
.removeClass()Method: Remove one or more classes from the selected element.

(2) Animation effects

jQuery also provides many animation effect methods for creating rich animation effects in the page. The following are some commonly used jQuery animation effect methods:

.hide()Method: Hide the selected element.
.show()Method: Display the selected element.
.fadeIn()Method: Fade the selected element.
.fadeOut()Method: Fade out the selected element.
.slideUp()Method: Slide the selected element up.
.slideDown()Method: Slide the selected element down.

(3) Ajax

Through Ajax operation, communication and data interaction with the server can be achieved without refreshing the entire page. jQuery provides some Ajax methods for implementing functions such as asynchronously requesting data and updating part of the page content in the page. Here are some commonly used Ajax methods in jQuery:

.load()Method: Load data from the server and insert it into the selected element.
.get()Method: Get data from the server.
.post()Method: Send data to the server.

3. Summary

jQuery is a simple, lightweight and convenient JavaScript library that greatly simplifies the work of JavaScript developers and enables processing of DOM, events, animations and other operations. becomes more convenient. From this article, we can learn about the usage, grammatical structure, common methods and application scenarios of jQuery. When learning jQuery, it is recommended to try more and perform page number optimization to improve page performance and user experience.

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