1)引入 CSS 依赖 (Importing CSS) 我很喜欢 CSS in JavaScript 这一理念。在 React 中,我们可以为每一个 React 组件引入相应的 CSS 文件,这一“梦想”成为了现实。在下面的代码示例,我把 CSS 文件的引入与其他依赖隔行分开,以示区别: importReact, {Component}from'react'import{observer}from'mobx-react'imp...
使用jQuery可以给元素很方便的添加class和删除class等操作,现在原生的JavaScript也可以实现这个方法了。使用classList可以方便的添加class、删除class、查询class等。 语法: let elementClass = element.classList; elementClasses 是一个 DOMTokenList 表示 element 的类属性 。如果类属性未设置或为空,那么 element...
我知道字段 firstName 确实存在于 html 中,但不确定为什么 javascript 无法读取该元素。 添加的 HTML: Melon Form <!-- load bootstrap via CDN --> Contact Form <!-- OUR FORM --> <!-- FIRST NAME -->
is supposed to be switched on/off on #dropdown-content when the user clicks on #hamburger-icon. It seems there are some complications in doing this with SVG elements and one solution proposed was to use the mentioned method. Despite implementing this method, the desired outcome is not ...
The getElementsByClassName() Method The HTML DOM Style Object Syntax element.classList Return Value TypeDescription ObjectADOMTokenList. A list of the class names of an element. Note TheclassListproperty is read-only, but you can use the methods listed below, to add, toggle or remove CSS cla...
To solve the "Cannot read property 'classList' of null" error, make sure the id you're using to get the DOM element is valid and exists in the DOM.
(the use of the JavaScriptapply()method), resulting in fewer lines of code. Because some browsers don’t support the API, we perform a check, and if it fails we display the message “API not supported”. If the browser does support the classList API, we attach a listener for theclick...
Assuming you have an element in the DOM: Get a reference to that DOM element: constel=document.querySelector("#el"); Then you can manipulate the classes on that element with theclassListmethod. // Add a classel.classList.add("open");// Add many classesel.classList.add("this","...
IfoldClassis present on the element, it is replaced bynewClass. IfoldClassis not present, this method has no effect. Returnstrueif the class was replaced,falseotherwise. Browser support This module has been tested for compatibility with IE8+, and may work in even older browsers. If it doesn...
if (!testElement.classList.contains("c2")) { var createMethod = function(method) { var original = DOMTokenList.prototype[method]; DOMTokenList.prototype[method] = function(token) { var i, len = arguments.length; for (i = 0; i < len; i++) { token = arguments[i]; original.call(...