How to write js in jquery

jQuery is a popular JavaScript library that simplifies many common JavaScript tasks. jQuery can be used for tasks such as document traversal, event handling, animation effects, and DOM manipulation. When writing JavaScript code with jQuery, be sure to follow some best practices to make your code clearer, understandable, and easier to maintain.

Here are some best practices for writing JavaScript in jQuery:

1. Correctly reference the jQuery library in the page

Before using jQuery, you must first refer to the page Introducing the jQuery library. Place the jQuery library inside the HEAD tag, making sure it is loaded before any code in the page that uses jQuery. For example:

2. Use the $(document).ready() method

In your JavaScript code, use the $(document).ready() method to ensure that the page's Document Object Model (DOM) is loaded before executing the code. This ensures that DOM elements have been loaded before trying to access them. For example:

$(document).ready(function() {
// Code
});

Or use abbreviation:

$(function () {
// Code
});

3. Use variables to cache jQuery selectors

If the same jQuery selector is used multiple times in the code, cache it Storing in a variable can improve the performance of your code. For example:

var $domElement = $('#dom-element');
$domElement.hide();
$domElement.show();

4. Avoid selecting the same element multiple times

When you need to perform multiple operations on the same element in code, it is best to cache it into a variable to avoid repeated selections. For example:

var $domElement = $('#dom-element');
$domElement.hide();
$domElement.show();

instead ：

$('#dom-element').hide();
$('#dom-element').show();

5. Use chain method

jQuery allows chained calls to multiple methods. This makes the code more concise and reduces the number of lines of code. For example:

$('#dom-element').addClass('active').show();

6. Explicitly specify the event namespace

Use naming Space helps avoid unintended side effects of events. For example:

$(document).on('click.someNamespace', function() {
// Code
});

$(document).off( '.someNamespace');

7. Use event delegation

When you need to attach events to many elements, using event delegation can reduce the number of lines of code and improve performance. For example:

$(document).on('click', '#dom-element', function() {
// Code
});

8. Use the class selector instead of the ID selector

The ID selector is slower than the class selector because the browser must search globally for all IDs in the HTML document, and the IDs must be unique within the same document. Therefore, using class selectors can improve performance. For example:

$('.dom-element').hide();

instead of:

$('#dom-element').hide() ;

9. Use the html() method instead of the text() method

When you need to modify the content of an element, using jQuery's html() method will be faster than the text() method. Because when using the text() method, the browser has to traverse the entire DOM tree to obtain the text of the element, but there is no need to do this when using the html() method. For example:

$('#dom-element').html('New content');

10. Caching DOM element attributes

When the same item needs to be accessed multiple times properties of an element, cache them into variables to improve performance.

var $domElement = $('#dom-element');
var elementOffset = $domElement.offset();

11. Use the $.ajax() method to process AJAX requests

Use jQuery's $.ajax() method to conveniently handle AJAX requests. The $.ajax() method allows you to specify the requested URL, HTTP method, data type, etc. For example:

$.ajax({
url: 'ajax-url',
method: 'POST',
data: {name: 'value'},
dataType : 'json',
success: function(data) {

// 成功的代码

},
error: function() {

// 错误的代码

}
});

In short, writing JavaScript code in jQuery requires following some best practices to make the code more readable, easy to maintain, and perform better.

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