What are the jquery centralized selectors?

jQuery is a well-known JavaScript library that provides some convenient methods to select, manipulate, and process HTML documents. Among them, selectors are one of the most commonly used functions of jQuery. jQuery provides a variety of selectors, and this article will introduce the centralized selector in detail.

Concentrated selector refers to a method of matching multiple elements at the same time through one selector. These selectors use commas as separators and write multiple selectors together to select elements that meet any selector condition. The following are some commonly used centralized selectors:

1. Universal selector

The universal selector refers to "*", which can match all elements in the page. Usually used to set some global styles or operations.

For example:

$('button,*').click(function() { alert('Clicked!'); });

This code snippet will add click events to all button buttons and all elements in the page. This method is obviously not the best method, and it is recommended to avoid using universal selectors as much as possible.

2. Category selector

Category selector refers to the selector starting with ".", which can select all elements with the same class name.

For example:

$('.myclass').css('background-color','gray');

This code snippet Set the background color of all elements with class "myclass" on the page to gray.

3. Element selector

Element selector refers to using the element name as the selector, which can select all elements that match the element name. For example:

$('div').addClass('highlight');

This code snippet adds a class of "highlight" to all div elements in the page " style.

4.id selector

The id selector refers to the selector starting with "#", which can select all elements matching the id. For example:

$('#myid').text();

This code snippet will get the text content of the element with the id "myid".

5. Child element selector

The child element selector refers to connecting two selectors with a ">" separator, which means that only the second matching child element of the element is selected. The selector element. For example:

$('div>p').css('color','red');

This code snippet will all the div elements in the page The font color of the inner p element is set to red.

6. Descendant element selector

The descendant element selector refers to connecting two selectors with a space separator, indicating that the selection of the element includes all descendant elements that match the second selector. element. For example:

$('div p').css('color','red');

This code snippet will all the div elements in the page And the font color of the p element in the descendant of the div element is set to red.

7. Union selector

Union selector refers to connecting multiple selectors with "," separator, which means selecting all elements that match any of the selector conditions. For example:

$('h1,p,a').addClass('italic');

This code snippet adds all h1, p and Add a style with class "italic" to the a element.

The above are the commonly used centralized selectors in jQuery. Choosing the appropriate selector can make us operate page elements more conveniently and efficiently.

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