Simple CSS Animation Loop – Fading In & Out “Loadi

问题:

Without Javascript, I'd like to make a simple looping CSS animation class that fades text in and out, infinitely. I don't know a lot about CSS animations, so I haven't figured it out yet, but here's how far I've gotten:

@keyframes flickerAnimation { /* flame pulses */
  0%   { opacity:1; }
  50%  { opacity:0; }
  100% { opacity:1; }
}
.animate-flicker {
    opacity:1;  
    animation: flickerAnimation 1s infinite;
}

回答1:

As King King said, you must add the browser specific prefix. This should cover most browsers:

@keyframes flickerAnimation {
  0%   { opacity:1; }
  50%  { opacity:0; }
  100% { opacity:1; }
}
@-o-keyframes flickerAnimation{
  0%   { opacity:1; }
  50%  { opacity:0; }
  100% { opacity:1; }
}
@-moz-keyframes flickerAnimation{
  0%   { opacity:1; }
  50%  { opacity:0; }
  100% { opacity:1; }
}
@-webkit-keyframes flickerAnimation{
  0%   { opacity:1; }
  50%  { opacity:0; }
  100% { opacity:1; }
}
.animate-flicker {
   -webkit-animation: flickerAnimation 1s infinite;
   -moz-animation: flickerAnimation 1s infinite;
   -o-animation: flickerAnimation 1s infinite;
    animation: flickerAnimation 1s infinite;
}

<div class="animate-flicker">Loading...</div>

回答2:

well looking for a simpler variation I found this:

it's truly smart, and I guess you might want to add other browsers variations too although it worked for me both on Chrome and Firefox.

demo and credit => http://codepen.io/Ahrengot/pen/bKdLC

@keyframes fadeIn { 
  from { opacity: 0; } 
}

.animate-flicker {
    animation: fadeIn 1s infinite alternate;
}

<h2 class="animate-flicker">Jump in the hole!</h2>

回答3:

To make more than one element fade in/out sequentially such as 5 elements fade each 4s,

1- make unique animation for each element with animation-duration equal to [ 4s (duration for each element) * 5 (number of elements) ] = 20s

animation-name: anim1 , anim2, anim3 ... 
animation-duration : 20s, 20s, 20s ... 

2- get animation keyframe for each element.

100% (keyframes percentage) / 5 (elements) = 20% (frame for each element)

3- define starting and ending point for each animation:

each animation has 20% frame length and @keyframes percentage always starts from 0%, so first animation will start from 0% and end in his frame(20%), and each next animation will starts from previous animation ending point and end when it reach his frame (+20% ),

@keyframes animation1 { 0% {}, 20% {}}
@keyframes animation2 { 20% {}, 40% {}}
@keyframes animation3 { 40% {}, 60% {}}
and so on

now we need to make each animation fade in from 0 to 1 opacity and fade out from 1 to 0,

so we will add another 2 points (steps) for each animation after starting and before ending point to handle the full opacity(1)

http://codepen.io/El-Oz/pen/WwPPZQ

.slide1 {
    animation: fadeInOut1 24s ease reverse forwards infinite
}

.slide2 {
    animation: fadeInOut2 24s ease reverse forwards infinite
}

.slide3 {
    animation: fadeInOut3 24s ease reverse forwards infinite
}

.slide4 {
    animation: fadeInOut4 24s ease reverse forwards infinite
}

.slide5 {
    animation: fadeInOut5 24s ease reverse forwards infinite
}

.slide6 {
    animation: fadeInOut6 24s ease reverse forwards infinite
}

@keyframes fadeInOut1 {
    0% { opacity: 0 }
    1% { opacity: 1 }
    14% {opacity: 1 }
    16% { opacity: 0 }
}

@keyframes fadeInOut2 {
    0% { opacity: 0 }
    14% {opacity: 0 }
    16% { opacity: 1 }
    30% { opacity: 1 }
    33% { opacity: 0 }
}

@keyframes fadeInOut3 {
    0% { opacity: 0 }
    30% {opacity: 0 }
    33% {opacity: 1 }
    46% { opacity: 1 }
    48% { opacity: 0 }
}

@keyframes fadeInOut4 {
    0% { opacity: 0 }
    46% { opacity: 0 }
    48% { opacity: 1 }
    64% { opacity: 1 }
    65% { opacity: 0 }
}

@keyframes fadeInOut5 {
    0% { opacity: 0 }
    64% { opacity: 0 }
    66% { opacity: 1 }
    80% { opacity: 1 }
    83% { opacity: 0 }
}

@keyframes fadeInOut6 {
    80% { opacity: 0 }
    83% { opacity: 1 }
    99% { opacity: 1 }
    100% { opacity: 0 }
}

回答4:

http://www.w3schools.com/cssref/css3_pr_animation-keyframes.asp

it is actually a browser issue... use -webkit- for chrome