How to randomly assign a color on hover effect - html

Question

I've never seen a hover effect like this before, and I'm trying to understand how it's achieved. You'll notice in this example, that when a user hovers over a link, the color the link turns can be any one 1 of 5 colors that are assigned within the style sheet (see below) at random.
How do you create this hover effect? Can it be done purely with CSS?
a:hover {
color:#1ace84;
text-decoration: none;
padding-bottom: 2px;
border: 0;
background-image: none;
}
a.green:hover { color: #1ace84; }
a.purple:hover { color: #a262c0; }
a.teal:hover { color: #4ac0aa; }
a.violet:hover { color: #8c78ba; }
a.pink:hover { color: #d529cd; }

Answer 1

Since a random factor is introduced, I don't think there's a way of doing it purely with CSS.
Here's my simple approach to the problem, using jQuery.
You can see a working example here: http://jsfiddle.net/GNgjZ/1/
$(document).ready(function()
{
$("a").hover(function(e)
{
var randomClass = getRandomClass();
$(e.target).attr("class", randomClass);
});
});
function getRandomClass()
{
//Store available css classes
var classes = new Array("green", "purple", "teal", "violet", "pink");
//Get a random number from 0 to 4
var randomNumber = Math.floor(Math.random()*5);
return classes[randomNumber];
}

Answer 2

The key piece of jQuery code is loaded in the footer of the page.
Please pay attention to the authors comment on the script, or seek the author's permission to reuse it.
/*
Code below this point is not licensed for reuse,
please look and learn but don't steal
*/
var lastUsed;
function randomFrom(arr){
var randomIndex = Math.floor(Math.random() * arr.length);
lastUsed = arr[randomIndex];
return lastUsed;
}
color_classes = ['green','purple','violet','teal','pink'];
function initLinks() {
$('#wrap a').hover(function() {
new_classes = color_classes.slice();
var index = $.inArray(lastUsed, new_classes);
new_classes.splice(index, 1);
var classes = $(this).attr('class');
if (classes) {
classes.split(' ');
$(classes).each(function(i, className) {
var index = $.inArray(className, new_classes);
if (index>0) {
new_classes.splice(index, 1);
}
});
}
$(this).removeClass(color_classes.join(' ')).addClass(randomFrom(new_classes));
}, function () {
});
}