How do I use CSS animations to slide a fixed position element from the bottom of the page to the top?

问题

http://jsfiddle.net/cD4Gr/1/

This is my animation code:

@-webkit-keyframes silde_to_top {
    0% {
        bottom: 0%;
        top: default;
    }
    100% {
        bottom: default;
        top: 0%;
        z-index: 1000000;
        opacity: 0.5;
    }
}

#test{
    -webkit-animation-name: silde_to_top;
    -webkit-animation-duration: 5s;
    -webkit-animation-timing-function: ease;
    -webkit-animation-iteration-count: 1;
    -webkit-animation-direction: normal;
    -webkit-animation-delay: 0;
    -webkit-animation-play-state: running;
    -webkit-animation-fill-mode: forwards;
}

currently, the div just auto-starts at the top, instead of sliding to the top. the only thing that animates is the opacity.

回答1:

It can't animate from a percent value to a default/auto value (or vice versa). This code gets it to work, albeit it starts offscreen:

@-webkit-keyframes silde_to_top {
  0% {
    top: 100%;
  }
  100% {
    top: 0%;
    z-index: 1000000;
    opacity: 0.5;
  }
}

Here's your fiddle example: http://jsfiddle.net/blineberry/cD4Gr/2/

来源：https://stackoverflow.com/questions/7931677/how-do-i-use-css-animations-to-slide-a-fixed-position-element-from-the-bottom-of