CSS animation-timing-function Property

Description

The animation-timing-function property determines the speed curve for the animation (a mathematical function is used - the cubic Bezier curve). The speed curve defines the animation time used to change one set of CSS styles to another.

Initial value: ease
Applies to: All elements, :before and :after pseudo elements
Inherited: No
Media: Visual
Computed value: As specified
Animatable: No
CSS Version: CSS3
JavaScript syntax: object.style.animationTimingFunction

Syntax

animation-timing-function: <single-timing-function> [ ',' <single-timing-function> ]*

Values

easeThe ease function is equivalent to cubic-bezier(0.25, 0.1, 0.25, 1).
linearThe linear function is equivalent to cubic-bezier(0, 0, 1, 1).
ease-inThe ease-in function is equivalent to cubic-bezier(0.42, 0, 1, 1).
ease-outThe ease-out function is equivalent to cubic-bezier(0, 0, 0.58, 1).
ease-in-outThe ease-in-out function is equivalent to cubic-bezier(0.42, 0, 0.58, 1)
step-startThe step-start function is equivalent to steps(1, start).
step-endThe step-end function is equivalent to steps(1, end).
steps(<integer>[, [ start | end ] ]?) Specifies a stepping function, described above, taking two parameters. The first parameter specifies the number of intervals in the function. It must be a positive integer (greater than 0). The second parameter, which is optional, is either the value 'start' or 'end', and specifies the point at which the change of values occur within the interval. If the second parameter is omitted, it is given the value 'end'.
cubic-bezier(<number>, <number>, <number>, <number>)Specifies a cubic-bezier curve. The four values specify points P1 and P2 of the curve as (x1, y1, x2, y2). Both x values must be in the range [0, 1] or the definition is invalid. The y values can exceed this range.

Example

HTML

<div class="progress"></div>

CSS

.progress { 
   background: #333;
   border: 2px solid #333; 
   height: 20px;
   position: relative; 
} 
.progress::before{ 
   animation: progress 5s; 
   animation-timing-function: linear; 
   animation-duration: 5s; 
   animation-fill-mode: forwards; 
   -webkit-animation-name: progress; 
   -webkit-animation-timing-function: linear; 
   -webkit-animation-duration: 5s; 
   -webkit-animation-fill-mode: forwards; 
   content: ""; 
   position: absolute; 
   height: 100%;  
   background: #FFA600; 
} 
@-webkit-keyframes progress { 
   from { 
      width: 0; 
   } 
   to { 
      width: 100%; 
   } 
} 
@keyframes progress { 
   from { 
      width: 0; 
   } 
   to { 
      width: 100%; 
   } 
}

Result