js 简版双色球 取号

<style type="text/css">
    span{
        display: block;
        float: left;
        width: 50px;
        height: 50px;
        border: 1px solid red;
        background-color: #000;
    }
    div{
        width: 520px;
        height: 520px;
        margin: 0 auto;
        overflow: hidden;
        border: 1px solid red;
    }
</style>
<div></div>
<button>start</button>
<h1></h1>
<script type="text/javascript">
    var div=document.getElementsByTagName('div')[0];
    var btn=document.getElementsByTagName('button')[0];
    var h1=document.getElementsByTagName('h1')[0];
    for(var i=1;i<34;i++){
        var span=document.createElement('span');
        span.innerHTML=i;
        div.appendChild(span);
    };
    var spans=div.getElementsByTagName('span');
    function white(obj){
        obj.style.backgroundColor="#fff";
    };
    function sortNumber(a,b){
        return a-b;
    };
    function checkRepeat(num,arr){
        for(var i=0,j=arr.length;i<j;i++){
            if (num==arr[i]) {
                return false;
            };
        };
        return true;
    };
    btn.onclick=function(){
        // 初始化
            h1.innerHTML="";
            for(var i=0,j=spans.length;i<j;i++){
                spans[i].style.backgroundColor="#000";
            }
        // 循环的到6个数
            var poor=[];
            for(var i=0,j=6;i<j;i++){
                var num=Math.floor(spans.length*Math.random());
                if (checkRepeat(num,poor)) {
                    poor.push(num);
                }else{
                    j++;
                };
            };
        // 排序
            var poorSort=poor.sort(sortNumber);
            // 另一种高效排序
                function quicksort(arr){
                    if (arr.length == 0)
                        return [];
                    var left = new Array();
                    var right = new Array();
                    var pivot = arr[0];
                    for (var i = 1; i < arr.length; i++) {
                        if (arr[i] < pivot) {
                           left.push(arr[i]);
                        } else {
                           right.push(arr[i]);
                        }
                    }
                    return left.concat(pivot, right);
                    // return quicksort(left).concat(pivot, quicksort(right));
                }
            // var poorSort=quicksort(poor);
        // 显示数据
            for(var i=0,j=poorSort.length;i<j;i++){
                white(spans[poorSort[i]]);
                h1.innerHTML=h1.innerHTML+parseInt(poorSort[i]+1);
                if (i<j-1) {
                  h1.innerHTML=h1.innerHTML+",";
                };
            };
    }
</script>