transition-timing-function - CSS（层叠样式表）

这是一个实验中的功能
此功能某些浏览器尚在开发中，请参考浏览器兼容性表格以得到在不同浏览器中适合使用的前缀。由于该功能对应的标准文档可能被重新修订，所以在未来版本的浏览器中该功能的语法和行为可能随之改变。

概述

CSS属性受到 transition effect的影响，会产生不断变化的中间值，而 CSS transition-timing-function 属性用来描述这个中间值是怎样计算的。实质上，通过这个函数会建立一条加速度曲线，因此在整个transition变化过程中，变化速度可以不断改变。

这条加速度曲线被<timing-function>所定义，之后作用到每个CSS属性的过渡.

你可以规定多个timing function,通过使用 transition-property属性，可以根据主列表(transition property的列表)给每个CSS属性应用相应的timing function.如果timing function的个数比主列表中数量少，缺少的值被设置为初始值（ease）。如果timing function比主列表要多，timing function函数列表会被截断至合适的大小。这两种情况下声明的CSS属性都是有效的。

初始值	`ease`
适用元素	all elements, `::before` and `::after` pseudo-elements
是否是继承属性	否
适用媒体	interactive
计算值	as specified
Animation type	discrete
正规顺序	the unique non-ambiguous order defined by the formal grammar

语法

Formal syntax: <timing-function>#where 
<timing-function> = linear | <cubic-bezier-timing-function> | <step-timing-function>
where 
<cubic-bezier-timing-function> = ease | ease-in | ease-out | ease-in-out | cubic-bezier(<number>, <number>, <number>, <number>)
<step-timing-function> = step-start | step-end | steps(<integer>[, <step-position>]?)
where 
<step-position> = jump-start | jump-end | jump-none | jump-both | start | end

transition-timing-function: ease
transition-timing-function: ease-in
transition-timing-function: ease-out
transition-timing-function: ease-in-out
transition-timing-function: linear
transition-timing-function: cubic-bezier(0.1, 0.7, 1.0, 0.1)
transition-timing-function: step-start
transition-timing-function: step-end
transition-timing-function: steps(4, end)

transition-timing-function: ease, step-start, cubic-bezier(0.1, 0.7, 1.0, 0.1)

transition-timing-function: inherit

值

<timing-function>: 通过transition-property中定义被过渡属性，每个 <timing-function>的值代表与这个属性相对应的timing function.

示例

transition-timing-function: ease

 <div class="parent">
  <div class="box">Lorem</div>
</div>

.parent { width: 250px; height:125px;}
.box {
    width: 100px;
    height: 100px;
    background-color: red;
    font-size: 20px;
    left: 0px;
    top: 0px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: ease;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: ease;
}
.box1{
    width: 50px;
    height: 50px;
    background-color: blue;
    color: yellow;
    font-size: 18px;
    left: 150px;
    top:25px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: ease;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: ease;
}

function updateTransition() {
  var el = document.querySelector("div.box");

  if (el) {
    el.className = "box1";
  } else {
    el = document.querySelector("div.box1");
    el.className = "box";
  }

  return el;
}

var intervalID = window.setInterval(updateTransition, 7000);

transition-timing-function: ease-in

 <div class="parent">
  <div class="box">Lorem</div>
</div>

.parent { width: 250px; height:125px;}
.box {
    width: 100px;
    height: 100px;
    background-color: red;
    font-size: 20px;
    left: 0px;
    top: 0px;
    position:absolute;
     -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: ease-in;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: ease-in;
}
.box1{
    width: 50px;
    height: 50px;
    background-color: blue;
    color: yellow;
    font-size: 18px;
    left: 150px;
    top:25px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: ease-in;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: ease-in;
}

function updateTransition() {
  var el = document.querySelector("div.box");

  if (el) {
    el.className = "box1";
  } else {
    el = document.querySelector("div.box1");
    el.className = "box";
  }

  return el;
}

var intervalID = window.setInterval(updateTransition, 7000);

transition-timing-function: ease-out

 <div class="parent">
  <div class="box">Lorem</div>
</div>

.parent { width: 250px; height:125px;}
.box {
    width: 100px;
    height: 100px;
    background-color: red;
    font-size: 20px;
    left: 0px;
    top: 0px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: ease-out;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: ease-out;
}
.box1{
    width: 50px;
    height: 50px;
    background-color: blue;
    color: yellow;
    font-size: 18px;
    left: 150px;
    top:25px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: ease-out;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: ease-out;
}

function updateTransition() {
  var el = document.querySelector("div.box");

  if (el) {
    el.className = "box1";
  } else {
    el = document.querySelector("div.box1");
    el.className = "box";
  }

  return el;
}

var intervalID = window.setInterval(updateTransition, 7000);

transition-timing-function: ease-in-out

 <div class="parent">
  <div class="box">Lorem</div>
</div>

.parent { width: 250px; height:125px;}
.box {
    width: 100px;
    height: 100px;
    background-color: red;
    font-size: 20px;
    left: 0px;
    top: 0px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: ease-in-out;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: ease-in-out;
}
.box1{
    width: 50px;
    height: 50px;
    background-color: blue;
    color: yellow;
    font-size: 18px;
    left: 150px;
    top:25px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: ease-in-out;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: ease-in-out;
}

function updateTransition() {
  var el = document.querySelector("div.box");

  if (el) {
    el.className = "box1";
  } else {
    el = document.querySelector("div.box1");
    el.className = "box";
  }

  return el;
}

var intervalID = window.setInterval(updateTransition, 7000);

transition-timing-function: linear

 <div class="parent">
  <div class="box">Lorem</div>
</div>

.parent { width: 250px; height:125px;}
.box {
    width: 100px;
    height: 100px;
    background-color: red;
    font-size: 20px;
    left: 0px;
    top: 0px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: linear;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: linear;
}
.box1{
    width: 50px;
    height: 50px;
    background-color: blue;
    color: yellow;
    font-size: 18px;
    left: 150px;
    top:25px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: linear;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: linear;
}

function updateTransition() {
  var el = document.querySelector("div.box");

  if (el) {
    el.className = "box1";
  } else {
    el = document.querySelector("div.box1");
    el.className = "box";
  }

  return el;
}

var intervalID = window.setInterval(updateTransition, 7000);

transition-timing-function: step-start

 <div class="parent">
  <div class="box">Lorem</div>
</div>

.parent { width: 250px; height:125px;}
.box {
    width: 100px;
    height: 100px;
    background-color: red;
    font-size: 20px;
    left: 0px;
    top: 0px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: step-start;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: step-start;
}
.box1{
    width: 50px;
    height: 50px;
    background-color: blue;
    color: yellow;
    font-size: 18px;
    left: 150px;
    top:25px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: step-start;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: step-start;
}

function updateTransition() {
  var el = document.querySelector("div.box");

  if (el) {
    el.className = "box1";
  } else {
    el = document.querySelector("div.box1");
    el.className = "box";
  }

  return el;
}

var intervalID = window.setInterval(updateTransition, 7000);

transition-timing-function: step-end

 <div class="parent">
  <div class="box">Lorem</div>
</div>

.parent { width: 250px; height:125px;}
.box {
    width: 100px;
    height: 100px;
    background-color: red;
    font-size: 20px;
    left: 0px;
    top: 0px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: step-end;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: step-end;
}
.box1{
    width: 50px;
    height: 50px;
    background-color: blue;
    color: yellow;
    font-size: 18px;
    left: 150px;
    top:25px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: step-end;
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: step-end;
}

function updateTransition() {
  var el = document.querySelector("div.box");

  if (el) {
    el.className = "box1";
  } else {
    el = document.querySelector("div.box1");
    el.className = "box";
  }

  return el;
}

var intervalID = window.setInterval(updateTransition, 7000);

transition-timing-function: steps(4, end)

 <div class="parent">
  <div class="box">Lorem</div>
</div>

.parent { width: 250px; height:125px;}
.box {
    width: 100px;
    height: 100px;
    background-color: red;
    font-size: 20px;
    left: 0px;
    top: 0px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: steps(4, end);
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: steps(4, end);
}
.box1{
    width: 50px;
    height: 50px;
    background-color: blue;
    color: yellow;
    font-size: 18px;
    left: 150px;
    top:25px;
    position:absolute;
    -webkit-transition-property: width height background-color font-size left top color;
    -webkit-transition-duration:2s;
    -webkit-transition-timing-function: steps(4, end);
    transition-property: width height background-color font-size left top color;
    transition-duration:2s;
    transition-timing-function: steps(4, end);
}

function updateTransition() {
  var el = document.querySelector("div.box");

  if (el) {
    el.className = "box1";
  } else {
    el = document.querySelector("div.box1");
    el.className = "box";
  }

  return el;
}

var intervalID = window.setInterval(updateTransition, 7000);

规范

Specification	Status	Comment
CSS Transitions transition-timing-function	Working Draft

浏览器兼容性

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Desktop
Mobile

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari
Basic support	(Yes)-webkit	4.0 (2.0)-moz 16.0 (16.0)	10	11.6-o 12.10 #	(Yes)-webkit

Feature	Android	Chrome for Android	Firefox Mobile (Gecko)	IE Mobile	Opera Mobile	Safari Mobile
Basic support	(Yes)-webkit	(Yes)-webkit	4.0 (2.0)-moz 16.0 (16.0)	?	?	(Yes)-webkit