How to use jquery basic selector

jQuery is a popular JavaScript library mainly used to simplify DOM manipulation and event handling. When using jQuery, selectors can help us locate elements and components easily. This article will explain how to use jQuery basic selectors.

1. Basic syntax

The selector is created through the jQuery function $() or jQuery(). Usually a selector is a string that describes the element or component we want to select. For example, to select all paragraph elements, you can use the following syntax:

$("p")

Multiple selectors can also be separated by commas within the same $() function. For example, to select all paragraphs and hyperlink elements, you can use the following syntax:

$("p,a")

2. Basic selectors

jQuery provides some basic selectors. The following are some commonly used basic selectors.

1. Element selector

The element selector selects a specific type of element. For example, to select all paragraph elements you can use the following syntax:

$("p")

2. ID Selector

The ID selector selects elements based on their ID attribute. For example, to select an element with the ID "myDiv" you can use the following syntax:

$("#myDiv")

3. Class selector

The class selector selects elements with a specific class. For example, to select an element with the class name "myClass" you can use the following syntax:

$(".myClass")

4. Attribute selector

Attribute selector can select elements with specific attribute values. For example, to select all hyperlink elements with href attributes, you can use the following syntax:

$("a[href]")

3. Combined selectors

The above basic selectors can be used in combination to implement more complex selectors. The following are some commonly used combination selectors.

1. Descendant selector

The descendant selector can select child elements within an element. For example, to select all paragraph elements under the ID "myDiv" you can use the following syntax:

$("#myDiv p")

2. Child element selector

Child element selector can select only child elements . For example, to select all li child elements with the ID "myList" you can use the following syntax:

$("#myList > li")

3. Sibling element selector

The sibling element selector can select the same as the target Elements that are adjacent to each other. For example, to select all div elements adjacent to the target element under the ID "myDiv", you can use the following syntax:

$("#myDiv + div")

4. Filter selector

In addition to the basic selector and combined selector , jQuery also provides many filter selectors, which can be selected based on the attributes, content, position and other conditions of the element.

The following are some commonly used filter selectors.

1. :first selector

:The first selector selects the first element that matches the selector. For example, to select the first li element, you can use the following syntax:

$("li:first")

2. :last selector

:The last selector can select the last element that matches the selector. For example, to select the last li element you can use the following syntax:

$("li:last")

3. :even and :odd selectors

:even and :odd selectors can select matching selectors of even and odd elements. For example, to select all even-numbered li elements in a list, you can use the following syntax:

$("li:even")

4. :contains selector

:contains selector can select elements based on their text content . For example, to select an li element containing the text "JavaScript" you can use the following syntax:

$("li:contains('JavaScript')")

5. :not selector

:the not selector can exclude elements with the specified selector . For example, to select all child elements that are not li elements under the ID "myList", you can use the following syntax:

$("#myList *:not(li)")

5. Summary

In jQuery, selectors are very powerful tools. Page elements and components can be easily and quickly positioned and manipulated. This article explains some common methods of basic selectors, combined selectors and filter selectors, hoping to help you better understand and use jQuery.

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