Analysis of the role of $ symbol in jQuery

This article mainly introduces the analysis of the role of the $ symbol in jQuery. It has a certain reference value. Now I share it with you. Friends in need can refer to it

$ symbol overall It has two functions:

1. Called as a general function: $(param)

(1), the parameter is a function: When the DOM is loaded, execute this callback function

　$(function(){//Execute after the DOM is loaded

　 //Code

　})

(2), the parameter is the selector string: find all matching tags and encapsulate them into jQuery objects

(3). The parameter is a dom object: encapsulate the dom object into a jQuery object

such as: $(this)

Note: The difference between jQuery objects and dom objects:

jQuery objects can use jQuery methods, but dom objects cannot!

　$("li")[0] is a dom object, and then wrapped by $() $($("li")[0] ) returns a jQuery object, then You can use jQuery method

(4), the parameter is html tag string (less used): create a tag object and encapsulate it into a jQuery object

2. Use as an object: $.xxx()

Such as:

(1) $.each(): Traverse the array Or object

(2) $.trim(): Remove the spaces at both ends

The above is the entire content of this article, I hope it will be useful for everyone’s learning Help, please pay attention to the PHP Chinese website for more related content!

Related recommendations:

How to use jquery to implement a sixty-second countdown

Analysis of DOM objects in JavaScript

Analysis of how NodeJS operates message queue RabbitMQ

The above is the detailed content of Analysis of the role of $ symbol in jQuery. For more information, please follow other related articles on the PHP Chinese website!