element.classList.contains(class); This works on all current browsers and there are polyfills to support older browsers too. Alternatively, if you work with older browsers and don’t want to use polyfills to fix them, usingindexOfis correct, but you have to tweak it a little: function h...
In JavaScript, you can use thecontains()method provided by theclassListobject to check if any element contains a specific CSS class. This method returnstrueif the class exists. Otherwise,falseis returned. Let us say we have the following HTML element: Subscribe Now And we want to check if ...
functionhasClass(element, className){ return(" "+ element.className +" ").indexOf(" "+className+" ") >-1; } 现在根据样式名称加” “的方式,判断一个元素是否含有该样式。在大部分的测试中,已经没有了问题。 但是!!!我们遇到了这样的神奇代码: 1 看上去和正常的代码没有太大区别,然而样式名称间...
JavaScript Element contains() 方法 contains()方法返回一个布尔值,指示节点是否是指定节点的后代。后代可以是孩子,孙子,曾孙等等。 实例: 找出元素是否是元素的后代: var span = document.getElementById("mySPAN"); var div = document.getElementById("myDIV").contains(span); 复制尝试一下 浏览器支...
如果作为一个函数(不带有运算符 new)调用时,Boolean() 只将把它的参数转换成一个原始的布尔值,并且返回这个值,如果省略 value 参数,或者设置为0、-0、null、""、false、undefined或NaN,则该对象设置为 false。否则设置为 true(即使 value 参数是字符串false)。
In this article, we'll take a look at how to check if an array includes/contains a value or element in JavaScript. Check Array of Primitive Values Includes a Value Array.includes() Function The simplest way to check for a primitive value in an array is to use the includes() method: ...
consta = [12,24,56,30,26,31,20,43];// The method checks whether the value is evenconstb= (element) => element ==24;console.log(a.some(b)); Output: Run Code Snippet Explanation: In the above example, we use some function to check if the array contains an element equal to24 ...
If you'd like to get a particular plugin instance, retrieve it directly from an element: $('[rel="popover"]').data('popover'). Default settings You can change the default settings for a plugin by modifying the plugin's Constructor.DEFAULTS object: Copy $.fn.modal.Constructor.DEFAULTS....
另外,本文工具函数的命名非常值得借鉴。 1. 第一部分:数组 1. `all`:布尔全等判断 代码语言:javascript 复制 constall=(arr,fn=Boolean)=>arr.every(fn);all([4,2,3],x=>x>1);// trueall([1,2,3]);// true 2. `allEqual`:检查数组各项相等 ...
1.根据 id 属性获取单个节点:getElementById 2.根据 name 属性获取节点列表:getElementsByNames 3.根据 标签名获取元素列表:getElementByTagName 4.根据 class 属性获取元素列表:getElementsByClassName 5.使用 CSS 选择器匹配第一个符合的元素:querySelector ...