当内容滚动到视图时激活CSS3关键帧动画 [英] Activate CSS3 keyframe animation when the content scrolls into view

问题描述

我一直在试图弄清楚如何让动画发生时，它滚动到视图，但很少或没有运气。我发现了一个JQuery插件Waypoints，但我缺乏使用它的技能。我试图使用CSS3关键帧动画时，它们滚动到视图。我做了一个突破，接近我想要完成的，但它不是我想要的地方。我有一个名为bounceinright的类，使项目反弹在屏幕的右侧。这里是CSS的：

I have been trying to figure out how to have animations occur when it is scrolled into view but with little to no luck. I found a JQuery plugin "Waypoints" but I lack the skills to utilize it. I am trying to use CSS3 keyframes that animate when they are scrolled into view. I made a breakthrough and am close to what I want to accomplish but it isn't quite where I want it. I have a class named "bounceinright" that makes the item bounce in to the right of the screen. Here is the CSS for that:

@-webkit-keyframes bounceinright {
0% {
    opacity: 0;
    -webkit-transform: translateX(2000px);
}

60% {
    opacity: 1;
    -webkit-transform: translateX(-30px);
}

80% {
    -webkit-transform: translateX(10px);
}

100% {
    -webkit-transform: translateX(0);
}
}

@-moz-keyframes bounceinright {
0% {
    opacity: 0;
    -moz-transform: translateX(2000px);
}

60% {
    opacity: 1;
    -moz-transform: translateX(-30px);
}

80% {
    -moz-transform: translateX(10px);
}

100% {
    -moz-transform: translateX(0);
}
}

@-o-keyframes bounceinright {
-o-transform: translateX(2000px);
}

60% {
opacity: 1;
-o-transform: translateX(-30px);
}

80% {
-o-transform: translateX(10px);
}

100% {
-o-transform: translateX(0);
}   
}

@keyframes bounceinright {
0% {
    opacity: 0;
    transform: translateX(2000px);
}

60% {
    opacity: 1;
    transform: translateX(-30px);
}

80% {
    transform: translateX(10px);
}

100% {
    transform: translateX(0);
}
 }

.bounceinright {
display: none;
}

.bounceinright.start {
-webkit-animation: bounceinright 1s ease-out forwards;
-moz-animation: bounceinright 1s ease-out forwards;
-ms-animation: bounceinright 1s ease-out forwards;
-o-animation: bounceinright 1s ease-out forwards;
animation: eigbounceinrighthty 1s ease-out forwards;
display: block;
}

然后我有一个JQuery代码片段， 开始。

and then I have a little JQuery snippet that will trigger the animation with the class "start" when it is scrolled to.

 ////////////////////////////////
 //scroll events
 ////////////////////////////////       
function isElementInViewport(elem) {
var $elem = $(elem);

// Get the scroll position of the page.
var scrollElem = ((navigator.userAgent.toLowerCase().indexOf('webkit') != -1) ? 'body' : 'html');
var viewportTop = $(scrollElem).scrollTop();
var viewportBottom = viewportTop + $(window).height();

// Get the position of the element on the page.
var elemTop = Math.round( $elem.offset().top );
var elemBottom = elemTop + $elem.height();

return ((elemTop < viewportBottom) && (elemBottom > viewportTop));
}

// Check if it's time to start the animation.
function checkAnimation() {
    var $elem = $('.row .wpb_content_element');

    // If the animation has already been started
    if ($elem.hasClass('start')) return;

    if (isElementInViewport($elem)) {
        // Start the animation
        $elem.addClass('start');
    }
}

// Capture scroll events
$(window).scroll(function(){
    checkAnimation();
});

我的问题是，当一个项目bounceinright滚动到，它触发所有的项目具有相同的类。我想知道是否有一种方法让他们单独触发，但同一类。

my problem though is that when one item with "bounceinright" is scrolled to, it triggers ALL of the items with the same class. I was wondering if there was a way to have them trigger individually but with the same class. Any help would be appreciated.

谢谢！

推荐答案

checkAnimation（）到

// Check if it's time to start the animation.
function checkAnimation() {
    var $elem = $('.row .wpb_content_element');

    $elem.each(function(){
        var $singleElement = $(this);
        // If the animation has already been started
        if ($singleElement.hasClass('start')) return;

        if (isElementInViewport($singleElement)) {
            // Start the animation
            $singleElement.addClass('start');
        }
    });
}

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