What is $() in jquery

$() in jquery is: 1. [$()] can be [$(expresion)]; 2. [$()] can be [$(element)], that is, a specific DOM element; 3. [$()] can be [$(funcTIon)], which is a function.

The operating environment of this tutorial: windows7 system, jquery3.2.1 version, thinkpad t480 computer.

$() in jquery is:

1. $() can be $(expresion), that is, css selector, Xpath Or html element, that is, the target element is matched through the above expression.

For example: The object constructed by $("a") uses a CSS selector to construct a jQuery object - it selects all the 7d01d0a03a49fceb57d12197d8d196cb tags. For example:

$("a").click(funcTIon(){...})

is the trigger event when any link on the page is clicked. To be precise, jQuery constructs an object $("a") using the tag 7d01d0a03a49fceb57d12197d8d196cb, and the function click() is an (event) method of this jQuery object.

The following statement is used to operate this HTML:

alert($("div>p").html());

$() is a query expression, that is, use "div>p" like this A query expression constructs a jQuery object, and then "html()" means to display its html content, which is the [two] of the above HTML code snippet. Another example:

$("<div><p>Hello</p></div>").appendTo("body");

$() contains a string. Use such a string to construct a jQuery object, and then add this string to b2636b4e0e32f7cd731b9073897693b7 .

2. $() can be $(element), which is a specific DOM element.

Commonly used DOM objects include document, location, form, etc. For example, this line of code: The document in

$(document).find("div>p").html());

$() is a DOM element, that is, it searches for the dc6dce4a544fdca2df29d5ac0ea9906b element with e388a4556c0f65e1904146cc1a846bee in the full text, and displays the content in e388a4556c0f65e1904146cc1a846bee.

3. $() can be $(funcTIon), which is a function, which is a shorthand for $(document).ready().

For example, the common form is this:

$(document).ready(funcTIon(){
alert("Hello world!");
});

Deformable operation:

$(function(){
alert("Hello world!");
});

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