What is $ in JQuery?

In JQuery, "$" is the alias of jQuery. It is a callback function provided by the jQuery library. It is defined as "select" and is the abbreviation of "selector"; the syntax "$(selector)" has the function It searches and selects elements in the HTML document based on the parameters in "()".

The operating environment of this tutorial: windows7 system, jquery3.6 version, Dell G3 computer.

What does "$" in jquery mean?

$ is a commonly used return function in JQuery, which is defined as "select". In English, it is the abbreviation of selector.

$ is actually another name for jQuery, and jQuery is provided by the jQuery library. a function.

This function can search and select elements in the html document based on the parameters in (). () can not only be IDs, but also various selectors

For example:

$(document)就是 选取整个文档对象

The role of jquery $ symbol

1. As a jQuery wrapper, use the selector to select DOM elements (this is also the most powerful function)

For example:

$("table tr:nth-child(even)")

2. Utility function, as the prefix of the namespace of several common utility functions

For example:

$.trim(someString)

3. Document ready handler , equivalent to $(document).ready(...)

For example: $(function(){...}); The function inside will be executed after the DOM tree is loaded

4. Create DOM elements

For example:

$("
how are you?
")

5. Extend jQuery

For example:

$.fn.disable = function(){...}

6. Use jQuery and other libraries

For example: the Prototype library also uses the $ symbol. jQuery provides the noConflict function to avoid conflicts. jQuery.noConflict(); restores the $ symbol to the meaning defined by the non-jQuery library.

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