将数组内的元素随机打乱

var a=["a","b","c","d"];

function shuffle(array) {
var currentIndex = array.length
, temporaryValue
, randomIndex
;
// While there remain elements to shuffle...
while (0 !== currentIndex) {
// Pick a remaining element...
randomIndex = Math.floor(Math.random() * currentIndex);
currentIndex -= 1;
// And swap it with the current element.
temporaryValue = array[currentIndex];
array[currentIndex] = array[randomIndex];
array[randomIndex] = temporaryValue;
}
return array;
}