按钮button倒计时

//按钮倒计时
     var wait = 7;
    document.getElementById("refreshParentBtn").onclick = function() {
        time(this);
    }
    function time(o) {
        if (wait == 0) {
            o.removeAttribute("disabled");
            o.innerHTML = "一键刷新";
            wait = 7;
        } else {
            o.setAttribute("disabled", true);
            o.innerHTML = "请稍后..(" + wait + ")";
            wait--;
            setTimeout(function() {
                time(o)
            }, 1000)
        }
    } 

<button type="button" id="refreshParentBtn" class="btn btn-primary btn-sm" data-dismiss="modal">点我刷新后倒计时</button>