Javascript滚动视差覆盖页面上的其他元素

Question

我找到了这个整洁流畅的滚动背景片段，并对其进行了微调。

我想要完成的是在开始时有这三个滚动背景，然后在最后一个完成后，页面上的其他 div 将显示。在我的示例中，无论您在 div 底部或上方放置什么信息，背景都会将其全部隐藏。

如果有一种更简单的方法来完成这种类型的平滑滚动，那就太好了，但我还没有找到像这样的方法。

https://jsfiddle.net/jzhang172/xwqsxeff/

$(function(){
// ------------- VARIABLES ------------- //
var ticking = false;
var isFirefox = (/Firefox/i.test(navigator.userAgent));
var isIe = (/MSIE/i.test(navigator.userAgent)) || (/Trident.*rv\:11\./i.test(navigator.userAgent));
var scrollSensitivitySetting = 30; //Increase/decrease this number to change sensitivity to trackpad gestures (up = less sensitive; down = more sensitive) 
var slideDurationSetting = 600; //Amount of time for which slide is "locked"
var currentSlideNumber = 0;
var totalSlideNumber = $(".background").length;

// ------------- DETERMINE DELTA/SCROLL DIRECTION ------------- //
function parallaxScroll(evt) {
  if (isFirefox) {
    //Set delta for Firefox
    delta = evt.detail * (-120);
  } else if (isIe) {
    //Set delta for IE
    delta = -evt.deltaY;
  } else {
    //Set delta for all other browsers
    delta = evt.wheelDelta;
  }

  if (ticking != true) {
    if (delta <= -scrollSensitivitySetting) {
      //Down scroll
      ticking = true;
      if (currentSlideNumber !== totalSlideNumber - 1) {
        currentSlideNumber++;
        nextItem();
      }
      slideDurationTimeout(slideDurationSetting);
    }
    if (delta >= scrollSensitivitySetting) {
      //Up scroll
      ticking = true;
      if (currentSlideNumber !== 0) {
        currentSlideNumber--;
      }
      previousItem();
      slideDurationTimeout(slideDurationSetting);
    }
  }
}

// ------------- SET TIMEOUT TO TEMPORARILY "LOCK" SLIDES ------------- //
function slideDurationTimeout(slideDuration) {
  setTimeout(function() {
    ticking = false;
  }, slideDuration);
}

// ------------- ADD EVENT LISTENER ------------- //
var mousewheelEvent = isFirefox ? "DOMMouseScroll" : "wheel";
window.addEventListener(mousewheelEvent, _.throttle(parallaxScroll, 60), false);

// ------------- SLIDE MOTION ------------- //
function nextItem() {
  var $previousSlide = $(".background").eq(currentSlideNumber - 1);
  $previousSlide.removeClass("up-scroll").addClass("down-scroll");
}

function previousItem() {
  var $currentSlide = $(".background").eq(currentSlideNumber);
  $currentSlide.removeClass("down-scroll").addClass("up-scroll");
}

});

html, body {
  overflow: hidden;
}

.background {
  background-size: cover;
  background-repeat: no-repeat;
  background-position: center center;
  overflow: hidden;
  will-change: transform;
  -webkit-backface-visibility: hidden;
          backface-visibility: hidden;
  height: 130vh;
  position: fixed;
  width: 100%;
  -webkit-transform: translateY(30vh);
      -ms-transform: translateY(30vh);
          transform: translateY(30vh);
  -webkit-transition: all 1.2s cubic-bezier(0.22, 0.44, 0, 1);
          transition: all 1.2s cubic-bezier(0.22, 0.44, 0, 1);
}
.background:before {
  content: "";
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(15, 23, 84, 0.32);
}
.background:first-child {
  background-image: url(http://s8.postimg.org/lf2udl5np/4_Aihmii.jpg);
  -webkit-transform: translateY(-15vh);
      -ms-transform: translateY(-15vh);
          transform: translateY(-15vh);
}
.background:first-child .content-wrapper {
  -webkit-transform: translateY(15vh);
      -ms-transform: translateY(15vh);
          transform: translateY(15vh);
}
.background:nth-child(2) {
  background-image: url(http://s8.postimg.org/ow4wgk4px/ugqti_Lg.jpg);
}
.background:nth-child(3) {
  background-image: url(http://s8.postimg.org/grwsbtiat/x_ZMOBTj.jpg);
}

/* Set stacking context of slides */
.background:nth-child(1) {
  z-index: 3;
}

.background:nth-child(2) {
  z-index: 2;
}

.background:nth-child(3) {
  z-index: 1;
}

.content-wrapper {
  height: 100vh;
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: center;
  -webkit-justify-content: center;
      -ms-flex-pack: center;
          justify-content: center;
  text-align: center;
  -webkit-flex-flow: column nowrap;
      -ms-flex-flow: column nowrap;
          flex-flow: column nowrap;
  color: #fff;
  font-family: Montserrat;
font-family: 'Libre Baskerville', serif;

  text-transform: uppercase;
  -webkit-transform: translateY(40vh);
      -ms-transform: translateY(40vh);
          transform: translateY(40vh);
  will-change: transform;
  -webkit-backface-visibility: hidden;
          backface-visibility: hidden;
  -webkit-transition: all 1.7s cubic-bezier(0.22, 0.44, 0, 1);
          transition: all 1.7s cubic-bezier(0.22, 0.44, 0, 1);
}
.content-title {
  font-size: 12vh;
  line-height: 1.4;
}

.background.up-scroll {
  -webkit-transform: translate3d(0, -15vh, 0);
          transform: translate3d(0, -15vh, 0);
}
.background.up-scroll .content-wrapper {
  -webkit-transform: translateY(15vh);
      -ms-transform: translateY(15vh);
          transform: translateY(15vh);
}
.background.up-scroll + .background {
  -webkit-transform: translate3d(0, 30vh, 0);
          transform: translate3d(0, 30vh, 0);
}
.background.up-scroll + .background .content-wrapper {
  -webkit-transform: translateY(30vh);
      -ms-transform: translateY(30vh);
          transform: translateY(30vh);
}

.background.down-scroll {
  -webkit-transform: translate3d(0, -130vh, 0);
          transform: translate3d(0, -130vh, 0);
}
.background.down-scroll .content-wrapper {
  -webkit-transform: translateY(40vh);
      -ms-transform: translateY(40vh);
          transform: translateY(40vh);
}
.background.down-scroll + .background:not(.down-scroll) {
  -webkit-transform: translate3d(0, -15vh, 0);
          transform: translate3d(0, -15vh, 0);
}
.background.down-scroll + .background:not(.down-scroll) .content-wrapper {
  -webkit-transform: translateY(15vh);
      -ms-transform: translateY(15vh);
          transform: translateY(15vh);
}

#one{
background:url(http://s8.postimg.org/lf2udl5np/4_Aihmii.jpg);
    background-repeat: no-repeat;
    background-size: cover;
}
#two{
background:red;
background:url(http://s8.postimg.org/ow4wgk4px/ugqti_Lg.jpg);
    background-repeat: no-repeat;
    background-size: cover;
}
#three{
background:url(http://s8.postimg.org/lf2udl5np/4_Aihmii.jpg);
    background-repeat: no-repeat;
    background-size: cover;
}

.content-subtitle{
text-transform:none;
}

#first{
color:black;
}
#second{
color:#0058FF;
}
#third{
color:rgb(236, 230, 216);
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.10.1/lodash.min.js"></script>
<div class="container">
  <section class="background" id="one">
    <div class="content-wrapper">
      <p class="content-title" id="first">Promise</p>
      <p class="content-subtitle">Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Cras ut massa mattis nibh semper pretium.<br />Nullam tristique urna sed tellus ornare congue. Etiam vitae erat at nibh aliquam dapibus.  </p>
    </div>
  </section>
  <section class="background" id="two">
    <div class="content-wrapper">
      <p class="content-title" id="second">Our Goal</p>
      <p class="content-subtitle">Blha blah</p>
    </div>
  </section>
  <section class="background" id="three">
    <div class="content-wrapper">
      <p class="content-title" id="third">Global</p>
      <p class="content-subtitle">blah blah</p>
    </div>
  </section>
</div>

<div>
Show me too and everything after the backgrounds please
</div>

旁注:如果您滚动到页面上的某处然后重新加载页面，则滚动会停留在当前位置，但初始背景也会停留。知道为什么吗？我假设它与 JS 有关。

Answer 1

有两件事阻碍了您的 div。首先是位置固定的 .background 和绝对位置的 .background:before。 (:before 标签基本上是在实际类之前放置一个元素。)

如果你只想在完成滚动背景后显示 div，请按照 CH 的回答并使用你的 js 对其进行操作。

但我假设您的其他 div 将继续像往常一样在背景 div 下方滚动。为此，您必须

1. 禁用 overflow:hidden at html, body 标签
2. 在 .background 处禁用 position:fixed
3. 在 js 中做一些定位以实现更平滑的过渡。

旁注:我已经在我的本地尝试了你的重新加载问题，一切正常