方法一：遍歷數(shù)組祟昭，利用indexOf方法判斷是否重復(fù)
var arr= ['a', 'a', 'b', 'b', 'c', 'c'];
var?array =[];
for(var i =0; i < arr.length; i++) {
????if(array.indexOf(arr[i]) ===-1) {array.push(arr[i]) }
?}
console.log(array);//['a', 'b', 'c']
方法二：遍歷數(shù)組缕坎，利用include方法判斷是否重復(fù)
var arr= ['a', 'a', 'b', 'b', 'c', 'c'];
var?array =[];
for(var i =0; i < arr.length; i++) {
????if(!array.includes(arr[i]) ) {array.push(arr[i]) }
}
console.log(array);//['a', 'b', 'c']
方法三：利用Array.from(new Set())去重，此法只能用于兼容ES6的瀏覽器
var arr= ['a', 'a', 'b', 'b', 'c', 'c'];
var?array =[];
array =?Array.from(new Set(arr));
console.log(array);//['a', 'b', 'c']
