custom-element

问题 dropdown menu is created in shadowDOM almost perfect, but the problem is how to hide the dropdown menu when click on any where else in window class NavComponent extends HTMLElement { constructor() { super(); let template = document.currentScript.ownerDocument.querySelector('template'); let clone = document.importNode(template.content, true); let root = this.attachShadow({ mode: 'open' }); root.appendChild(clone); } connectedCallback() { let ddc = this.shadowRoot.querySelectorAll('

问题 I am trying to create a web component that is usable in a form element specifically, that has a name , and a value . I recognize that I can create a web component that extends an HTMLInputElement : <input is="very-extended"> but I am trying to create an entirely new element. When creating a regular web component, you can create it from the prototype of a regular HTMLElement ( HTMLElement.prototype ). Which leads me to assume that I can create a different element with the prototype of an

问题 I just started learning about the HTML custom elements, and through reading a series of intros, tutorials, and documentation, I think I have a good handle on how it works, but I have a philosophical question on the proper way to use or not use the <template> tag. Custom elements give you the ability to encapsulate new functionality, simplifying the structure of your HTML document, and allowing you to simply insert a <my-custom-element>...</my-custom-element> tag instead of <div class="my

问题 Whilst this may seem to be a duplicate question those asked previously have been based around Polymer, not native CustomElements, and this is about the css itself, not penetrating the ShadowDOM or Custom CSS Properties / Variables So here we have a simple Custom Element (note: as of writing this only works in newer Chrome versions) class StyleMe extends HTMLElement { constructor () { super(); let shadow = this.attachShadow({ mode: 'closed' }); shadow.appendChild(document.querySelector('#style

问题 Here is my problem: Aurelia app: a few custom elements (already sharing a view via @UseView) doing almost the same thing (specific func shoud be defined by every element itself), how to manage shared code (inkl @bindable)? How to refactor this: https://gist.run/?id=897298ab1dad92fadca77f64653cf32c 回答1: The "shared" code you refer to in your question is lifecycle-related stuff in your custom elements, which isn't really suited for sharing. You would need to do inheritance, and with custom

问题 Is it possible to pass a class expression as parameter? Have not tried the eval route yet.. // CardtsElements.Zone contains a valid class expression // used to create a valid Zone Custom Element let extend = (source, name, definitionClassExpression) => customElements.define('CARDTS-' + name, class extends CardtsElements[source] definitionClassExpression); ^^^^SYNTAX ERROR^^^^^^^^^^ // Create a new 'CARDTS-FOUNDATION' element extending 'CARDTS-ZONE' extend('Zone','Foundation', { static get

问题 Here's a function that returns the width of an image, given the image's url: async function getImageWidthByUrl(imgUrl) { const imgEl = document.createElement("img"); let untilImgLoaded = new Promise((resolve, reject) => { imgEl.onload = resolve; imgEl.onerror = reject; }); imgEl.src = imgUrl; await untilImgLoaded; return imgEl.naturalWidth; } It works fine. It also (of course) works if we use new Image() instead of document.createElement("img") . However, the document.createElement("img")

问题 The HTML spec describes several kinds of elements stored in the CustomElementRegistry . Builtin elements like <a> that are represented by a builtin subclass of HTMLElement like HTMLAnchorElement . Autonomous custom elements like <my-element> which extend HTMLElement and register with the CustomElementRegistry . Customized builtin elements like <a is="my-link"> which extend a subclass of HTMLElement and use the is="customized-tag-name" to specify the class. Legacy elements like <isindex> which

问题 I tried this Angular Elements Demo I downloaded, installed, and built that demo on local. Then, used the following code: <!doctype html> <html lang="en"> <head> <meta charset="utf-8"> <title>Angular Elements Demo</title> </head> <body> <hello-world name="Anna"></hello-world> <script src="dist/main.js"></script> <script> const helloCp = document.querySelector('hello-world'); helloCp.addEventListener('hi', (data) => { console.log(data.detail); }); setTimeout(() => { helloCp.setAttribute('name',

问题 I'm developing a web application that uses HTML 5 native web components. My problem is that I have a lot of common CSS for all of these and I use font awesome to have nice icons. Right now I put all my styles inside "/deep" shadow piercing but Chrome says : "/deep/ combinator is deprecated." Do you have any suggestions on how can I have global CSS and CSS libraries (like font awesome) available on the whole app ? Thanks :) 回答1: You could include the CSS font file globally, with the <link rel=