What is the method for manipulating element attributes in jquery?-Front-end Q&A-php.cn

Home

Web Front-end

Front-end Q&A

What is the method for manipulating element attributes in jquery?

青灯夜游

Mar 18, 2022 pm 06:59 PM

jquery

The methods for operating element attributes are: 1. Methods for operating class attributes, including addClass(), hasClass(), removeClass(), toggleClass(); 2. Methods for operating specified attributes, including attr() , prop(), removeAttr().

What is the method for manipulating element attributes in jquery?

The operating environment of this tutorial: windows7 system, jquery1.12.4 version, Dell G3 computer.

jQuery property operation method

Method	Description
addClass()	Add the specified class name (class attribute value) to the matching element.
attr()	Sets or returns the attributes and values of the matching element.
prop()	Set or return the properties and values of the matching element.
hasClass()	Checks whether the matching element has the specified class.
removeAttr()	Removes the specified attribute from all matching elements.
removeClass()	Remove all or specified classes from all matching elements.
toggleClass()	Adds or removes a class from the matching element.

jQuery attr() and prop() methods return or set attributes

prop() method Similar to the attr() method, both are used to get or set the HTML attributes of elements, but there are essential differences between the two.

jQuery official recommendation: For attributes with two values of true and false, such as checked, selected, disabled, etc., it is recommended to use the prop() method to operate, while for other attributes it is recommended to use the attr() method. to operate.

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <script src="js/jquery-1.12.4.min.js"></script>
    <script>
        $(function () {
            $(&#39;input[type="radio"]&#39;).change(function(){
                var bool = $(this).attr("checked");
                if(bool){
                    $("p").text("你选择的是：" + $(this).val());
                }
            })
        })
    </script>
</head>
<body>
    <div>
        <label><input type="radio" name="fruit" value="苹果" />苹果</label>
        <label><input type="radio" name="fruit" value="香蕉" />香蕉</label>
        <label><input type="radio" name="fruit" value="西瓜" />西瓜</label>
    </div>
    <p></p>
</body>
</html>

What is the method for manipulating element attributes in jquery?

In this example, we actually want to determine whether the radio button is checked by $(this).attr("checked") , if selected, get the value of the radio button. But after running the code, I found: It has no effect at all! Why is this?

In fact, we cannot obtain the checked, selected, and disabled attributes of the form element using the attr() method, but must use the prop() method. Therefore, it will work if we replace the attr() method with the prop() method.

In fact, the prop() method appears to make up for the shortcomings of the attr() method in form attribute operations. Remember one sentence: If a property cannot be obtained or set using the attr() method, it can be achieved by changing the prop() method.

removeAttr() method removes attributes

In jQuery, we can use the removeAttr() method to delete an attribute of an element.

Grammar:

$().removeAttr("属性名")

jQuery class name operation

Class name operation refers to adding a class or Remove a class to control the style of the element as a whole.

In jQuery, there are three types of CSS class name operations.

Add class.
Delete class.
Switch class.

addClass() method to add a class

In jQuery, we can use the addClass() method to add a class to an element.

Syntax:

$().addClass("类名")

removeClass() method deletes a class

In jQuery, we can use the removeClass() method to delete a class for an element .

Syntax:

$().removeClass("类名")

toggleClass() method switches class

In jQuery, we can use the toggleClass() method to switch class names for elements. Toggle actually means "switch". We will be exposed to this word a lot in the future, such as toggle(), slideToggle(), etc. Friends should pay attention and compare.

Syntax:

$().toggleClass("类名")

toggleClass() method is used to check whether an element has a certain class. If the class does not exist, the class is added to the element; if the class already exists, the class is removed from the element.

[Recommended learning: jQuery video tutorial, web front-end]

The above is the detailed content of What is the method for manipulating element attributes in jquery?. For more information, please follow other related articles on the PHP Chinese website!

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Optimizing Performance with useState() in React ApplicationsApr 27, 2025 am 12:22 AM

useState()iscrucialforoptimizingReactappperformanceduetoitsimpactonre-rendersandupdates.Tooptimize:1)UseuseCallbacktomemoizefunctionsandpreventunnecessaryre-renders.2)EmployuseMemoforcachingexpensivecomputations.3)Breakstateintosmallervariablesformor

Sharing State Between Components Using Context and useState()Apr 27, 2025 am 12:19 AM

Use Context and useState to share states because they simplify state management in large React applications. 1) Reduce propdrilling, 2) The code is clearer, 3) It is easier to manage global state. However, pay attention to performance overhead and debugging complexity. The rational use of Context and optimization technology can improve the efficiency and maintainability of the application.

The Impact of Incorrect Keys on React's Virtual DOM UpdatesApr 27, 2025 am 12:19 AM

Using incorrect keys can cause performance issues and unexpected behavior in React applications. 1) The key is a unique identifier of the list item, helping React update the virtual DOM efficiently. 2) Using the same or non-unique key will cause list items to be reordered and component states to be lost. 3) Using stable and unique identifiers as keys can optimize performance and avoid full re-rendering. 4) Use tools such as ESLint to verify the correctness of the key. Proper use of keys ensures efficient and reliable React applications.

Understanding Keys in React: Optimizing List RenderingApr 27, 2025 am 12:13 AM

InReact,keysareessentialforoptimizinglistrenderingperformancebyhelpingReacttrackchangesinlistitems.1)KeysenableefficientDOMupdatesbyidentifyingadded,changed,orremoveditems.2)UsinguniqueidentifierslikedatabaseIDsaskeys,ratherthanindices,preventsissues

Common Mistakes to Avoid When Working with useState() in ReactApr 27, 2025 am 12:08 AM

useState is often misused in React. 1. Misunderstand the working mechanism of useState: the status will not be updated immediately after setState. 2. Error update status: SetState in function form should be used. 3. Overuse useState: Use props if necessary. 4. Ignore the dependency array of useEffect: the dependency array needs to be updated when the state changes. 5. Performance considerations: Batch updates to states and simplified state structures can improve performance. Correct understanding and use of useState can improve code efficiency and maintainability.

React's SEO-Friendly Nature: Improving Search Engine VisibilityApr 26, 2025 am 12:27 AM

Yes,ReactapplicationscanbeSEO-friendlywithproperstrategies.1)Useserver-siderendering(SSR)withtoolslikeNext.jstogeneratefullHTMLforindexing.2)Implementstaticsitegeneration(SSG)forcontent-heavysitestopre-renderpagesatbuildtime.3)Ensureuniquetitlesandme

React's Performance Bottlenecks: Identifying and Optimizing Slow ComponentsApr 26, 2025 am 12:25 AM

React performance bottlenecks are mainly caused by inefficient rendering, unnecessary re-rendering and calculation of component internal heavy weight. 1) Use ReactDevTools to locate slow components and apply React.memo optimization. 2) Optimize useEffect to ensure that it only runs when necessary. 3) Use useMemo and useCallback for memory processing. 4) Split the large component into small components. 5) For big data lists, use virtual scrolling technology to optimize rendering. Through these methods, the performance of React applications can be significantly improved.

Alternatives to React: Exploring Other JavaScript UI Libraries and FrameworksApr 26, 2025 am 12:24 AM

Someone might look for alternatives to React because of performance issues, learning curves, or exploring different UI development methods. 1) Vue.js is praised for its ease of integration and mild learning curve, suitable for small and large applications. 2) Angular is developed by Google and is suitable for large applications, with a powerful type system and dependency injection. 3) Svelte provides excellent performance and simplicity by compiling it into efficient JavaScript at build time, but its ecosystem is still growing. When choosing alternatives, they should be determined based on project needs, team experience and project size.

See all articles