jQuery is a popular JavaScript library that simplifies common web development tasks such as HTML document traversal, event handling, animation effects, and AJAX. When using jQuery, we need to become familiar with some important objects and functions. This article will introduce the main objects of jQuery to help you better use and understand jQuery.
- $(selector)
$(selector) is the core object of jQuery, which can find elements that meet specific conditions in the DOM tree. The selector can be any CSS selector, such as element name, class name, ID, etc. For example, use $("p") to get all paragraph elements; use $("#myId") to get the element with the ID "myId".
- $(this)
$(this) represents the currently selected element and is usually used when handling events. For example, when the user clicks a button, we can use $(this) to get the button element and perform the corresponding operation.
- $(document)
$(document) represents the entire HTML document, including the root node and all child nodes. Use $(document) to perform operations at the document level, such as binding global events, modifying the document structure, etc.
- $(window)
$(window) represents the current browser window, which is often used in web development to handle events such as window size changes and scrolling. For example, we can use $(window).width() to get the width of the current window.
- $(selector).parent()
The parent() method returns the parent element of the current element, which can be used to traverse up the DOM tree. For example, use $("p").parent() to get the parent element of all paragraph elements.
- $(selector).children()
The children() method returns all child elements of the current element, which can be used to traverse downwards in the DOM tree. For example, use $("ul").children() to get all list item elements.
- $(selector).siblings()
siblings() method returns all sibling elements of the current element, which can be used to traverse horizontally in the DOM tree. For example, use $("li").siblings() to get all sibling list item elements.
- $(selector).find()
The find() method finds elements that meet specific conditions in the subtree of the current element and can be used for deep traversal. For example, use $("ul").find("li") to get all list item elements.
- $(selector).addClass()
The addClass() method adds one or more class names to the current element and can be used to modify the style of the element. For example, use $("p").addClass("highlight") to add a highlight effect to all paragraph elements.
- $(selector).removeClass()
The removeClass() method removes one or more class names from the current element and can be used to modify the style of the element. For example, use $("p").removeClass("highlight") to remove the highlight effect from all paragraph elements.
- $(selector).attr()
attr() method gets or sets the attribute value of the current element and can be used to operate the attributes of the element. For example, use $("a").attr("href") to get the URL addresses of all link elements.
- $(selector).data()
The data() method gets or sets the data of the current element and can be used to transfer data between elements. For example, use $("div").data("msg", "Hello world!") to save a message data in all DIV elements.
The above are some common objects and methods in jQuery, covering many aspects such as DOM tree traversal, style modification, attribute operation and data transfer. Mastering these objects and methods, we can develop web pages more flexibly and implement more functions.
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