获取字符串中某子串出现的次数和位置

<script type="text/javascript"> 
    var str ='abcabcabcabcabcabda';
    function timesAndPlace(str){
        var times = str.match(/ab/g).length;
        console.log(times); //次数

        var placeArr = [];
        var index = 0;
        for(var i=0;i<times;i++){
            var place = str.indexOf('ab',index);
            if(place != -1){
                placeArr.push(place);
                index = place+2;
            }
        }
        console.log(placeArr); //位置
    }
    timesAndPlace(str);
    </script>