How to use the CSS3 transition property

Along with the introduction of CSS3 comes many new features that are available for use in creating great effects; one of the most useful is the transition property.

The transition property is an important new development in CSS. It can be used to create a dynamic change effect on a div or class using a simple structure:

transition: property duration timing-function delay;

CSS3′s transition is a great way to add a little animation to sites without the large overhead of a JavaScript library like jQuery.

Demo

Before we start, you can see a demo here of the transition property in action.

Property

Firstly, in order for the transition property to work, the standard property that it will be applied to needs to be defined. Arguably the two most common properties that will be defined are width and height. To write the property standalone simply use:

transition-property: define property

Size Change

Following on, once the property has been defined then the start and end values need to be assigned. In the case of values such as width or height the property needs to be set with a start value and then an end value with some other condition.

For example, here we set the transition property to width, then the start value of width and then set the end value when the element is hovered over:

#mainheader {
    transition-property:width;
    width:50px; 
}
#mainheader:hover {
    width:75px;
}

Duration

Now that we have defined the property to transform, the start and end values, we need to define the duration of the transition. This is achieved by defining a length in either seconds or milliseconds as below:

transition-duration: duration;

Building this into the example the following code is created:

#mainheader {
    transition-property:width;
    transition-duration:0.5s; 
    width:500px;
}
#mainheader:hover {
    width:750px;
}

This means that the mainheader div will expand by 25px over a duration of 5 seconds.

Timing Function

The code is sufficient to create a nice effect however we can further utilise the CSS3 transition property by using timing-function Using this property it is possible to alter the speed curve of the transition duration. The transition property is set to a linear curve by default. However, you can define ease, ease-in, ease-out, ease-in-out and even cubic-bezier to alter the speed curve. Cubic-bezier allows you to define your own values using (n,n,n,n) where n can be between 0 and 1 (for example linear would be (0,0,1,1)).

Adding in this code to our example results in:

#mainheader {
    transition-property:width;
    transition-timing-function:ease-in-out; 
    transition-duration:0.5s; 
    width:500px;
}
#mainheader:hover {
    width:750px;
}

Delay

Furthermore, much like transition-duration, using the transition-delay property defines a pause before the transition effect begins:

transition-delay: time;

Conclusion

Finally, it is important to consider two things when using the CSS3 transition property. Firstly, most browsers in circulation at present require a browser prefix to use it (the exceptions being IE10, Opera and Firefox16+):

-moz-transition: for Firefox 15
-webkit-transition: for Chrome and Safari

(Bear in mind that IE9 and lower does not support the transition property at all.)

Secondly, although I’ve used long hand in the examples above for clarity, it’s considered best practice to write in short form, as follows:

#mainheader {
    -moz-transition: width ease-in-out 0.5s 0.1s; /* for Firefox 15 */
    -webkit-transition: width ease-in-out 0.5s 0.1s; /* for Chrome and Safari */
    transition: width ease-in-out 0.5s 0.1s;
    width:500px;
}
#mainheader:hover {
    width:750px;
}