javascript - js 移动端 手指按住实现数字递增的问题

Question

代码是基于jquery的

var intervalEvent = null;
$("#join_input_jia,#join_input_jian").on({
        touchstart: function(e){
            e.preventDefault();
            var type = 1;
            if($(this).attr('id') == 'join_input_jian'){
                type = 2;
            }
            if(!isNull(intervalEvent)){
                window.clearInterval(intervalEvent);
            }
            intervalEvent = setInterval("countChange(" + type + ")", 100);
        },
        touchmove: function(e){
            window.clearInterval(intervalEvent);
        },
        touchend: function(e){
            window.clearInterval(intervalEvent);
        }
});

function countChange(type){
    var _userBuyCount = $("#join_count").val();
    if(type === 1){
        if (parseInt(_userBuyCount) >= availablecount) {
            toast("最多只能参与" + availablecount + "人次");
            window.clearInterval(intervalEvent);
            return;
        }
        //对全局的userBuyCount赋值
        userBuyCount = _userBuyCount;
        $("#join_count").val(parseInt(_userBuyCount) + purchasespanFromPostData);
    }else if(type === 2){
        if (parseInt(_userBuyCount) <= purchasespanFromPostData) {
            window.clearInterval(intervalEvent);
            return;
        }
        //对全局的userBuyCount赋值
        userBuyCount = _userBuyCount;
        $("#join_count").val(parseInt(_userBuyCount) - purchasespanFromPostData);
    }
};

我想实现的效果是按住按钮join_input_jia,输入框的值一直递增,join_input_jian则一直递减, 现在这段代码是实际运行中改来改去都不行,是不是还要加按住的时间判断之类的,求思路