210 lines
7.0 KiB
HTML
210 lines
7.0 KiB
HTML
<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8" />
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<meta name="viewport" content="width=device-width, initial-scale=1.0" />
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<title>shadow DOM</title>
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</head>
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<body>
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<fancy-tabs background>
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<button slot="title">Tab 1</button>
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<button slot="title" selected>Tab 2</button>
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<button slot="title">Tab 3</button>
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<section>content panel 1</section>
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<section>content panel 2</section>
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<section>content panel 3</section>
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</fancy-tabs>
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<script>
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(function () {
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'use strict';
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// Feature detect
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if (!(window.customElements && document.body.attachShadow)) {
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document.querySelector('fancy-tabs').innerHTML =
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"<b>Your browser doesn't support Shadow DOM and Custom Elements v1.</b>";
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return;
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}
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let selected_ = null;
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// See https://www.w3.org/TR/wai-aria-practices-1.1/#tabpanel
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customElements.define(
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'fancy-tabs',
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class extends HTMLElement {
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constructor() {
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super(); // always call super() first in the ctor.
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// Create shadow DOM for the component.
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let shadowRoot = this.attachShadow({ mode: 'open' });
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shadowRoot.innerHTML = `
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<style>
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:host {
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display: inline-block;
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width: 650px;
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font-family: 'Roboto Slab';
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contain: content;
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}
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:host([background]) {
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background: var(--background-color, #9E9E9E);
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border-radius: 10px;
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padding: 10px;
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}
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#panels {
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box-shadow: 0 2px 2px rgba(0, 0, 0, .3);
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background: white;
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border-radius: 3px;
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padding: 16px;
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height: 250px;
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overflow: auto;
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}
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#tabs {
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display: inline-flex;
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-webkit-user-select: none;
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user-select: none;
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}
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#tabs slot {
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display: inline-flex; /* Safari bug. Treats <slot> as a parent */
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}
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/* Safari does not support #id prefixes on ::slotted
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See https://bugs.webkit.org/show_bug.cgi?id=160538 */
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#tabs ::slotted(*) {
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font: 400 16px/22px 'Roboto';
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padding: 16px 8px;
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margin: 0;
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text-align: center;
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width: 100px;
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text-overflow: ellipsis;
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white-space: nowrap;
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overflow: hidden;
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cursor: pointer;
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border-top-left-radius: 3px;
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border-top-right-radius: 3px;
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background: linear-gradient(#fafafa, #eee);
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border: none; /* if the user users a <button> */
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}
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#tabs ::slotted([aria-selected="true"]) {
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font-weight: 600;
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background: white;
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box-shadow: none;
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}
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#tabs ::slotted(:focus) {
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z-index: 1; /* make sure focus ring doesn't get buried */
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}
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#panels ::slotted([aria-hidden="true"]) {
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display: none;
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}
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</style>
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<div id="tabs">
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<slot id="tabsSlot" name="title"></slot>
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</div>
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<div id="panels">
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<slot id="panelsSlot"></slot>
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</div>
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`;
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}
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get selected() {
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return selected_;
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}
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set selected(idx) {
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selected_ = idx;
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this._selectTab(idx);
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// Updated the element's selected attribute value when
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// backing property changes.
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this.setAttribute('selected', idx);
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}
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connectedCallback() {
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this.setAttribute('role', 'tablist');
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const tabsSlot = this.shadowRoot.querySelector('#tabsSlot');
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const panelsSlot = this.shadowRoot.querySelector('#panelsSlot');
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this.tabs = tabsSlot.assignedNodes({ flatten: true });
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this.panels = panelsSlot
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.assignedNodes({ flatten: true })
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.filter((el) => {
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return el.nodeType === Node.ELEMENT_NODE;
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});
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// Add aria role="tabpanel" to each content panel.
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for (let [i, panel] of this.panels.entries()) {
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panel.setAttribute('role', 'tabpanel');
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panel.setAttribute('tabindex', 0);
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}
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// Save refer to we can remove listeners later.
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this._boundOnTitleClick = this._onTitleClick.bind(this);
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this._boundOnKeyDown = this._onKeyDown.bind(this);
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tabsSlot.addEventListener('click', this._boundOnTitleClick);
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tabsSlot.addEventListener('keydown', this._boundOnKeyDown);
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this.selected = this._findFirstSelectedTab() || 0;
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}
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disconnectedCallback() {
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const tabsSlot = this.shadowRoot.querySelector('#tabsSlot');
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tabsSlot.removeEventListener('click', this._boundOnTitleClick);
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tabsSlot.removeEventListener('keydown', this._boundOnKeyDown);
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}
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_onTitleClick(e) {
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if (e.target.slot === 'title') {
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this.selected = this.tabs.indexOf(e.target);
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e.target.focus();
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}
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}
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_onKeyDown(e) {
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switch (e.code) {
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case 'ArrowUp':
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case 'ArrowLeft':
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e.preventDefault();
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var idx = this.selected - 1;
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idx = idx < 0 ? this.tabs.length - 1 : idx;
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this.tabs[idx].click();
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break;
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case 'ArrowDown':
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case 'ArrowRight':
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e.preventDefault();
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var idx = this.selected + 1;
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this.tabs[idx % this.tabs.length].click();
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break;
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default:
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break;
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}
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}
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_findFirstSelectedTab() {
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let selectedIdx;
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for (let [i, tab] of this.tabs.entries()) {
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tab.setAttribute('role', 'tab');
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// Allow users to declaratively select a tab
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// Highlight last tab which has the selected attribute.
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if (tab.hasAttribute('selected')) {
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selectedIdx = i;
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}
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}
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return selectedIdx;
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}
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_selectTab(idx = null) {
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for (let i = 0, tab; (tab = this.tabs[i]); ++i) {
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let select = i === idx;
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tab.setAttribute('tabindex', select ? 0 : -1);
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tab.setAttribute('aria-selected', select);
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this.panels[i].setAttribute('aria-hidden', !select);
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}
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}
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},
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);
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})();
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</script>
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</body>
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</html>
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