[Introduction] Previously we introduced some newly added selectors in HTML5, namely querySelector(), querySelectorAll() and getElementsByClassName(). These three have their own unique functions. If necessary, you can read the relevant content in HTML5 actual combat and analysis. Today, I have introduced to you some newly added selectors in HTML5, namely querySelector(), querySelectorAll() and getElementsByClassName(). These three have their own unique functions. If necessary, you can read the relevant content in HTML5 actual combat and analysis. Today I will introduce to you the classList attribute.
What exactly does the classList attribute do? Let’s leave classList alone for now. We consider the question, that is, how do we delete one of the class names among elements with multiple class names? Menglong struggled with his brain and finally came up with a way to achieve it. Delete the class name meng among the three class names li, meng and long. The code is as follows
HTML code
<p class="li meng long">梦龙小站</p>
- JavaScript code
//获取要删除类名meng的p var p = document.getElementsByTagName("p")[0]; //获取类名字符串并拆分成数组 var allClassName = p.className.split(" "); //找到要删除的类名 var i, len, pos = -1; for(i=0, len = allClassName.length; i < len; i++){ if(allClassName[i] == "meng"){ pos = i; break; } } //删除类名 allClassName.splice(pos, 1); alert(allClassName) //li,long //将其余的类名拼成字符串并重新添加到元素的类名中 p.className = allClassName.join(" ");
Preview effect
<p class="li meng long">梦龙小站</p>JavaScript code
//获取要删除类名meng的p var p = document.getElementsByTagName("p")[0]; alert(p.classList) //li meng long p.classList.remove("meng") alert("p.className: " + p.className) //p.className: li longPreview effect
<p class="li meng long">梦龙小站</p>
//获取要删除类名meng的p var p = document.getElementsByTagName("p")[0]; alert(p.classList.contains("meng")) //true alert(p.classList.contains("menglong")) //false
3. add(value)
HTML code
<p class="li meng long">梦龙小站</p>JavaScript code
//添加类名 menglong //获取要删除类名meng的p var p = document.getElementsByTagName("p")[0]; p.classList.add("menglong"); alert("p.className: " + p.className) //p.className: li meng long menglongPreview effect
<p class="li meng long">梦龙小站</p>JavaScript code梦龙小站
//切换类名 meng //获取要删除类名li的p var p = document.getElementsByTagName("p"); var i, len; for(i=0, len = p.length; i< len; i++){ p[i].classList.toggle("meng"); } alert("p[0].className: " + p[0].className) //p[0].className: li long alert("p[1].className: " + p[1].className) //p[1].className: li meng longPreview effect
The above is the detailed content of classList attribute in HTML5. For more information, please follow other related articles on the PHP Chinese website!

HTML5 code consists of tags, elements and attributes: 1. The tag defines the content type and is surrounded by angle brackets, such as. 2. Elements are composed of start tags, contents and end tags, such as contents. 3. Attributes define key-value pairs in the start tag, enhance functions, such as. These are the basic units for building web structure.

HTML5 is a key technology for building modern web pages, providing many new elements and features. 1. HTML5 introduces semantic elements such as, , etc., which enhances web page structure and SEO. 2. Support multimedia elements and embed media without plug-ins. 3. Forms enhance new input types and verification properties, simplifying the verification process. 4. Offer offline and local storage functions to improve web page performance and user experience.

Best practices for H5 code include: 1. Use correct DOCTYPE declarations and character encoding; 2. Use semantic tags; 3. Reduce HTTP requests; 4. Use asynchronous loading; 5. Optimize images. These practices can improve the efficiency, maintainability and user experience of web pages.

Web standards and technologies have evolved from HTML4, CSS2 and simple JavaScript to date and have undergone significant developments. 1) HTML5 introduces APIs such as Canvas and WebStorage, which enhances the complexity and interactivity of web applications. 2) CSS3 adds animation and transition functions to make the page more effective. 3) JavaScript improves development efficiency and code readability through modern syntax of Node.js and ES6, such as arrow functions and classes. These changes have promoted the development of performance optimization and best practices of web applications.

H5 is not just the abbreviation of HTML5, it represents a wider modern web development technology ecosystem: 1. H5 includes HTML5, CSS3, JavaScript and related APIs and technologies; 2. It provides a richer, interactive and smooth user experience, and can run seamlessly on multiple devices; 3. Using the H5 technology stack, you can create responsive web pages and complex interactive functions.

H5 and HTML5 refer to the same thing, namely HTML5. HTML5 is the fifth version of HTML, bringing new features such as semantic tags, multimedia support, canvas and graphics, offline storage and local storage, improving the expressiveness and interactivity of web pages.

H5referstoHTML5,apivotaltechnologyinwebdevelopment.1)HTML5introducesnewelementsandAPIsforrich,dynamicwebapplications.2)Itsupportsmultimediawithoutplugins,enhancinguserexperienceacrossdevices.3)SemanticelementsimprovecontentstructureandSEO.4)H5'srespo

The tools and frameworks that need to be mastered in H5 development include Vue.js, React and Webpack. 1.Vue.js is suitable for building user interfaces and supports component development. 2.React optimizes page rendering through virtual DOM, suitable for complex applications. 3.Webpack is used for module packaging and optimize resource loading.


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