如何使渐变合并到导航栏而不是“弹出”颜色变化？

问题描述 投票：0回答：1

我正在尝试使粘性导航栏进入渐变状态，然后在其固定位置返回黑色，但是当它移动时，它应该平滑地合并到渐变中。

当我使用导航栏向下滚动并从黑色变为渐变时，它可以工作，但当我返回时，它会弹出为黑色，而不是平滑过渡。怎么办？

我希望渐变具有与向下滚动时相同的行为，但当我向上滚动时，它不会执行相同的操作。

window.addEventListener("scroll", function () {
  const navbar = document.querySelector(".navbar");
  const scrollToTopBtn = document.getElementById("scrollToTopBtn");
  const img = scrollToTopBtn.querySelector("img");

  // Handle navbar background transition
  if (window.pageYOffset > 21) {
    navbar.classList.add("scrolled");
  } else {
    navbar.classList.remove("scrolled");
  }
});
body,
html {
  margin: 0;
  padding: 0;
  font-family: Arial, sans-serif;
  scroll-behavior: smooth;
  height: 2000px; /* For demonstration purposes */
}
.navbar {
  position: -webkit-sticky; /* For Safari */
  position: sticky;
  top: 21px; /* Sets the navbar 21px from the top */
  width: 100%;
  background-color: black; /* Start with a black background */
  transition: background 0.5s ease; /* Smooth transition for background */
  z-index: 1050;
}
.navbar.scrolled {
  background: radial-gradient(
    circle,
    rgba(0, 0, 0, 0.7) 70%,
    rgba(0, 0, 0, 0)
  ); /* Background gradient on scroll */
}
.navbar-dark .navbar-nav .nav-link {
  color: rgba(255, 255, 255, 0.55);
}
.navbar-dark .navbar-nav .nav-link:hover,
.navbar-dark .navbar-nav .nav-link:focus {
  color: rgba(255, 255, 255, 0.75);
}
.navbar-dark .navbar-nav .nav-link.active {
  color: #fff; /* Ensure this is white */
}
.navbar-nav .nav-link.active,
.navbar-nav .nav-link.show {
  color: turquoise;
}
.navbar-nav {
  flex-direction: row !important; /* Ensures navbar items are in a row */
}
.dropdown-menu {
  position: absolute !important; /* Ensures dropdown opens as an overlay */
}
.nav-link {
  color: white !important; /* Customize color as needed */
}
.navbar-nav {
  display: flex;
  flex-direction: row; /* Inline display */
  justify-content: center;
  align-items: center; /* This ensures vertical alignment is centered */
  width: 100%; /* Ensures the navbar takes full width */
}
.container-fluid {
  display: flex;
  flex-wrap: wrap; /* Allows items to wrap in smaller screens */
  align-items: center; /* Vertical alignment */
  justify-content: space-between; /* Horizontal spacing */
  width: 100vw;
}
@media (max-width: 768px) {
  .navbar-nav {
    flex-direction: column; /* Stack the links vertically on small screens */
  }
  .nav-link {
    padding: 0px 30px; /* Adjust padding for smaller screens */
    text-align: center; /* Center-align the text */
  }
}
.scroll-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  cursor: pointer;
  background-color: #fff;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
  transition: background-color 0.3s;
}
.scroll-to-top:hover {
  background-color: #f8f8f8;
}
.scroll-to-top img {
  width: 40px;
  height: 40px;
  transition: transform 2s linear;
}
.scroll-to-top:hover img {
  transform: rotate(360deg);
}
#scrollToTopBtn {
  position: fixed;
  bottom: 20px;
  right: 30px;
  padding: 10px;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  display: none; /* Hidden by default */
  z-index: 1000; /* Make sure it's above other content */
  outline: none;
}
#scrollToTopBtn img {
  width: 60px;
  height: 60px;
}
<!doctype html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Navbar Scroll Effect</title>
    <link
      rel="stylesheet"
      href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css" />
  </head>
  <body>
    <nav class="navbar navbar-expand-lg navbar-dark">
      <div class="container-fluid">
        <ul class="navbar-nav">
          <li class="nav-item">
            <a class="nav-link active" href="#">Home</a>
          </li>
          <li class="nav-item dropdown">
            <a
              class="nav-link dropdown-toggle"
              href="#drawings"
              id="navbarDropdownMenuLink"
              role="button"
              data-bs-toggle="dropdown"
              aria-expanded="false">
              Drawings
            </a>
            <ul class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
              <li><a class="dropdown-item" href="#">Drawing 1</a></li>
              <li><a class="dropdown-item" href="#">Drawing 2</a></li>
              <li><a class="dropdown-item" href="#">Drawing 3</a></li>
              <li><a class="dropdown-item" href="#">Drawing 4</a></li>
              <li><a class="dropdown-item" href="#">Drawing 5</a></li>
            </ul>
          </li>
        </ul>
      </div>
    </nav>
    <button id="scrollToTopBtn" onclick="window.scrollTo({top: 0, behavior: 'smooth'});">
      <img
        src="https://upload.wikimedia.org/wikipedia/commons/thumb/1/17/Yin_yang.svg/1024px-Yin_yang.svg.png" alt="Go to top" />
    </button>
    <script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js"></script>
  </body>
</html>

javascript html css bootstrap-4
1个回答
0
投票

您可以使用 @property 来设置渐变百分比和颜色的动画。

但是firefox不支持。

@property --p {
  syntax: "<percentage>";
  inherits: false;
  initial-value: 100%;
}
@property --c {
  syntax: "<color>";
  inherits: false;
  initial-value: black;
}
.navbar {
  --p: 100%;
  --c: black;
  background: radial-gradient(circle, var(--c) var(--p), transparent); /* Start with a black background */
  transition: --p 0.5s, --c 0.5s; /* Smooth transition for background */
}
.navbar.scrolled {
  --p: 70%;
  --c: rgba(0, 0, 0, 0.7);
}


window.addEventListener("scroll", function () {
  const navbar = document.querySelector(".navbar");
  const scrollToTopBtn = document.getElementById("scrollToTopBtn");
  const img = scrollToTopBtn.querySelector("img");

  // Handle navbar background transition
  if (window.pageYOffset > 21) {
    navbar.classList.add("scrolled");
  } else {
    navbar.classList.remove("scrolled");
  }
});
body,
html {
  margin: 0;
  padding: 0;
  font-family: Arial, sans-serif;
  scroll-behavior: smooth;
  height: 2000px; /* For demonstration purposes */
}
@property --p {
  syntax: "<percentage>";
  inherits: false;
  initial-value: 100%;
}
@property --c {
  syntax: "<color>";
  inherits: false;
  initial-value: black;
}
.navbar {
  --p: 100%;
  --c: black;
  position: -webkit-sticky; /* For Safari */
  position: sticky;
  top: 21px; /* Sets the navbar 21px from the top */
  width: 100%;
  background: radial-gradient(circle, var(--c) var(--p), transparent); /* Start with a black background */
  transition: --p 0.5s, --c 0.5s; /* Smooth transition for background */
  z-index: 1050;
}
.navbar.scrolled {
  --p: 70%;
  --c: rgba(0, 0, 0, 0.7);
}
.navbar-dark .navbar-nav .nav-link {
  color: rgba(255, 255, 255, 0.55);
}
.navbar-dark .navbar-nav .nav-link:hover,
.navbar-dark .navbar-nav .nav-link:focus {
  color: rgba(255, 255, 255, 0.75);
}
.navbar-dark .navbar-nav .nav-link.active {
  color: #fff; /* Ensure this is white */
}
.navbar-nav .nav-link.active,
.navbar-nav .nav-link.show {
  color: turquoise;
}
.navbar-nav {
  flex-direction: row !important; /* Ensures navbar items are in a row */
}
.dropdown-menu {
  position: absolute !important; /* Ensures dropdown opens as an overlay */
}
.nav-link {
  color: white !important; /* Customize color as needed */
}
.navbar-nav {
  display: flex;
  flex-direction: row; /* Inline display */
  justify-content: center;
  align-items: center; /* This ensures vertical alignment is centered */
  width: 100%; /* Ensures the navbar takes full width */
}
.container-fluid {
  display: flex;
  flex-wrap: wrap; /* Allows items to wrap in smaller screens */
  align-items: center; /* Vertical alignment */
  justify-content: space-between; /* Horizontal spacing */
  width: 100vw;
}
@media (max-width: 768px) {
  .navbar-nav {
    flex-direction: column; /* Stack the links vertically on small screens */
  }
  .nav-link {
    padding: 0px 30px; /* Adjust padding for smaller screens */
    text-align: center; /* Center-align the text */
  }
}
.scroll-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  cursor: pointer;
  background-color: #fff;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
  transition: background-color 0.3s;
}
.scroll-to-top:hover {
  background-color: #f8f8f8;
}
.scroll-to-top img {
  width: 40px;
  height: 40px;
  transition: transform 2s linear;
}
.scroll-to-top:hover img {
  transform: rotate(360deg);
}
#scrollToTopBtn {
  position: fixed;
  bottom: 20px;
  right: 30px;
  padding: 10px;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  display: none; /* Hidden by default */
  z-index: 1000; /* Make sure it's above other content */
  outline: none;
}
#scrollToTopBtn img {
  width: 60px;
  height: 60px;
}
<!doctype html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Navbar Scroll Effect</title>
    <link
      rel="stylesheet"
      href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css" />
  </head>
  <body>
    <nav class="navbar navbar-expand-lg navbar-dark">
      <div class="container-fluid">
        <ul class="navbar-nav">
          <li class="nav-item">
            <a class="nav-link active" href="#">Home</a>
          </li>
          <li class="nav-item dropdown">
            <a
              class="nav-link dropdown-toggle"
              href="#drawings"
              id="navbarDropdownMenuLink"
              role="button"
              data-bs-toggle="dropdown"
              aria-expanded="false">
              Drawings
            </a>
            <ul class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
              <li><a class="dropdown-item" href="#">Drawing 1</a></li>
              <li><a class="dropdown-item" href="#">Drawing 2</a></li>
              <li><a class="dropdown-item" href="#">Drawing 3</a></li>
              <li><a class="dropdown-item" href="#">Drawing 4</a></li>
              <li><a class="dropdown-item" href="#">Drawing 5</a></li>
            </ul>
          </li>
        </ul>
      </div>
    </nav>
    <button id="scrollToTopBtn" onclick="window.scrollTo({top: 0, behavior: 'smooth'});">
      <img
        src="https://upload.wikimedia.org/wikipedia/commons/thumb/1/17/Yin_yang.svg/1024px-Yin_yang.svg.png" alt="Go to top" />
    </button>
    <script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js"></script>
  </body>
</html>

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