js+css实现自定义风格的下拉选择框效果代码-html代码-BFW代码库

代码语言：html
代码描述：js+css实现自定义风格的下拉选择框效果代码
下面为部分代码预览，完整代码请点击下载或在bfwstudio webide中打开
<!DOCTYPE html>
<html lang="en" >
<head>
  <meta charset="UTF-8">

  <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover"><link rel='stylesheet' href='https://fonts.googleapis.com/css2?family=DM+Sans&amp;display=swap'>
  
  <style>
      @charset "UTF-8";
* {
  border: 0;
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --hue: 223;
  --bg: hsl(0,0%,100%);
  --fg: hsl(var(--hue),10%,10%);
  --trans-dur: 0.3s;
  --trans-ease-in-out: cubic-bezier(0.65,0,0.35,1);
  --trans-ease-out: cubic-bezier(0.33,1,0.68,1);
  font-size: calc(20px + (40 - 20) * (100vw - 280px) / (3840 - 280));
}

body,
button {
  color: var(--fg);
  font: 1em/1.5 "DM Sans", sans-serif;
  transition: background-color var(--trans-dur), color var(--trans-dur);
}

body {
  background-color: var(--bg);
  display: flex;
  height: 100vh;
}

main {
  margin: auto;
  padding: 0.75em 0;
  width: min-content;
  height: 12em;
}

.drop {
  --drop-trans-dur: 0.5s;
  --drop-flare-dist: 0;
  border-radius: 0.5em;
  margin: auto;
  padding: 0.25em 0.25em 0 0.25em;
  position: relative;
  min-width: 9em;
}
.drop, .drop:after {
  background-color: hsl(var(--hue), 10%, 90%);
  transition: background-color var(--trans-dur);
}
.drop:before, .drop:after {
  content: "";
  position: absolute;
}
.drop:before {
  background-image: radial-gradient(100% 100% at 100% 50%, hsla(var(--hue), 90%, 50%, 0.5), hsla(var(--hue), 90%, 50%, 0) 50%);
  display: none;
  right: 0;
  bottom: 100%;
  width: 9em;
  height: 9em;
}
.drop:after {
  border-radius: 0.4375em;
  display: block;
  top: 0.125em;
  left: 0.125em;
  width: calc(100% - 0.25em);
  height: calc(100% - 0.25em);
}
.drop__btn {
  background-color: white;
  border-radius: 0.375em;
  box-shadow: 0 0 0 0.25em hsla(var(--hue), 90%, 50%, 0);
  cursor: pointer;
  display: flex;
  align-items: center;
  line-height: 1;
  height: 2.5em;
  outline: transparent;
  margin-bottom: 0.25em;
  padding: 0.75em;
  position: relative;
  width: 100%;
  transition: background-color var(--trans-dur), box-shadow calc(var(--trans-dur) / 2) var(--trans-ease-in-out), color var(--drop-trans-dur);
  -webkit-appearance: none;
  appearance: none;
  -webkit-tap-highlight-color: transparent;
  z-index: 1;
}
.drop__btn:hover, .drop__btn:focus-visible, .drop__btn[aria-expanded=true] {
  background-color: hsl(var(--hue), 10%, 95%);
}
.drop__btn:focus-visible {
  box-shadow: 0 0 0 0.25em hsla(var(--hue), 90%, 50%, 1);
}
.drop__btn:after {
  border-top: 0.375em solid currentColor;
  border-right: 0.375em solid transparent;
  border-left: 0.375em solid transparent;
  content: "";
  display: block;
  margin-inline-start: auto;
  width: 0;
  height: 0;
  transform-origin: 50% 37.5%;
  transition: transform var(--drop-trans-dur) var(--trans-ease-out);
}
.drop__btn[aria-expanded=true]:after {
  transform: rotate(0.5turn);
}
.drop--collapsing, .drop--expanding, .drop__items {
  overflow: hidden;
}
.drop__items {
  height: 0;
}
.drop__items-inner {
  visibility: hidden;
}
.drop--collapsing .drop__btn[aria-expanded=true] {
  background-color: white;
}
.drop--collapsing .drop__btn[aria-expanded=true]:after {
  transform: rotate(0);
}
.drop--expanding:before {
  display: block;
}
.drop__items .drop__btn:hover, .drop__items .drop__btn:focus-visible {
  background-color: hsl(var(--hue), 10%, 97.5%);
  color: hsla(var(--hue), 90%, 50%);
}
.drop__items .drop__btn:focus-visible {
  box-shadow: 0 0 0 0.25em hsla(var(--hue), 90%, 50%, 0);
}
.drop__items .drop__btn:after {
  border: 0;
  content: "✓";
  display: none;
  width: auto;
  height: auto;
}
.drop__items .drop__btn--selected:after {
  display: block;
}
.drop__btn[aria-expanded=true] ~ .drop__items {
  height: auto;
}
.drop__btn[aria-expanded=true] ~ .drop__items .drop__items-inner {
  visibility: visible;
}
.drop:has([aria-expanded=true]) {
  height: auto;
}
.drop:has([aria-expanded=true]):before {
  transform: translateY(calc(9em + var(--drop-flare-dist)));
  transition: transform var(--drop-trans-dur) linear;
}

/* Dark theme */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: hsl(var(--hue),10%,10%);
    --fg: hsl(var(--hue),10%,90%);
  }

  .drop, .drop:after {
    background-color: black;
  }
  .drop__btn {
    background-color: hsl(var(--hue), 10%, 10%);
  }
  .drop__btn:hover, .drop__btn:focus-visible, .drop__btn[aria-expanded=true] {
    background-color: hsl(var(--hue), 10%, 20%);
  }
  .drop__items .drop__btn:hover, .drop__items .drop__btn:focus-visible {
    background-color: hsl(var(--hue), 10%, 15%);
    color: hsla(var(--hue), 90%, 70%);
  }
  .drop--collapsing .drop__btn[aria-expanded=true] {
    background-color: hsl(var(--hue), 10%, 10%);
  }
}
  </style>

</head>
<body>

<main>
	<div class="drop" id="dummy">
		<button class="drop__btn" aria-expanded="false" aria-haspopup="true" type="button"></button>
		<div class="drop__items" data-items>
			<div class="drop__items-inner">
				<button class="drop__btn" type="button" value="windows">Windows</button>
				<button class="drop__btn" type="button" value="mac">Mac</button>
				<button class="drop__btn" type="button" value="linux">Linux</button>
			</div>
		</div>
	</div>
</main>

  <script  >
      "use strict";
window.addEventListener("DOMContentLoaded", () => {
    const drop = new DropdownMenu("#dummy");
});
class DropdownMenu {
    /**
     * @param el CSS selector of the menu
    */
    constructor(el) {
        var _a, _b, _c;
        /** Animation objects */
        this.animations = [];
        /** Options for this menu */
        this.options = [
            { name: "windows", friendlyName: "Windows" },
            { name: "mac", friendlyName: "Mac" },
            { name: "linux", friendlyName: "Linux" }
        ];
        /** Selected option by name */
        this.selected = "windows";
        /** Menu is collapsing */
        this.isCollapsing = false;
        /** Menu is expanding */
        this.isExpanding = false;
        /** Actions to run after collapsing the item. */
        this.animActionsCollapse = {
            onfinish: this.onAnimationFinish.bind(this, false),
            oncancel: () => { this.isCollapsing = false; }
        };
        /** Actions to run after expanding the item. */
        this.animActionsExpand = {
            onfinish: this.onAnimationFinish.bind(this, true),
            oncancel: () => { this.isExpanding = false; }
        };
        this.el = document.querySelector(el);
        this.menuButton = (_a = this.el) === null || _a === void 0 ? void 0 : _a.querySelector("button");
        this.itemList = (_b = this.el) === null || _b === void 0 ? void 0 : _b.querySelector("[data-items]");
        this.defaultOption();
        document.addEventListener("click", this.outsideToClose.bind(this));
        window.addEventListener("keydown", this.escToClose.bind(this));
        (_c = this.el) === null || _c === void 0 ? void 0 : _c.addEventListener("click", this.toggle.bind(this));
        window.addEventListener("keydown", this.kbdAction.bind(this));
    }
    /** Transition duration specific to the menu */
    get transDuration() {
        if (this.el) {
            const style = getComputedStyle(this.el);
            const rawDur = style.getPropertyValue("--drop-trans-dur");
            let dur = rawDur.substring(0, rawDur.indexOf("s"));
            const mIndex = dur.indexOf("m");
            if (mIndex > -1) {
                dur = dur.substring(0, mIndex);
                return +dur;
            }
            // seconds to milliseconds
            return +dur * 1e3;
        }
        return 0;
    }
    /** Display the default selected option. */
    defaultOption() {
        var _a;
        const buttonEl = (_a = this.itemList) === null || _a === void 0 ? void 0 : _a.querySelector(`[value="${this.selected}"]`);
        buttonEl === null || buttonEl === void 0 ? void 0 : buttonEl.classList.add("drop__btn--selected");
        if (this.menuButton) {
            const optionFound = this.options.find(option => option.name === this.selected);
            this.menuButton.textContent = (optionFound === null || optionFound === void 0 ? void 0 : optionFound.friendlyName) || "";
        }
    }
    /**
     * Navigate the menu options with arrow keys.
     * @param e Keydown event
     */
    kbdAction(e) {
        var _a;
        const { key } = e;
        const tabOrArrow = key === "Tab" || key === "ArrowUp" || key === "ArrowDown";
        const notAnimating = !this.isExpanding && !this.isCollapsing;
        i.........完整代码请登录后点击上方下载按钮下载查看