JS-定时器管理实例函数封装

/**
 * Created by 12461 on 2016/11/6.
 */
window.onload = function () {
    var oBtn1 = document.getElementById('btn1');
    var oBtn2 = document.getElementById('btn2');
    var oDiv = document.getElementById('div1');
    //外面尽量不要放变量
    // var timer = null;
    oDiv.timer = null;
    oBtn1.onclick = function () {
      doMove(oDiv,-10,10);
    };
    oBtn2.onclick = function () {
        doMove(oDiv,10,800);
    };
    //运动的函数
    function doMove(obj,dir,target) {
        //先清除定时器
        clearInterval(obj.timer);
        //设置定时器
        obj.timer = setInterval(function () {
            var speed = parseInt(getStyle(obj,'left')) + dir ;
            //往前跑
            if (speed > target && dir>0){
                speed = target;
            }
            //往后跑
            if (speed < target && dir < 0){
                speed = target;
            }
            obj.style.left = speed + 'px';
        },30);
    }
    //拿到样式的函数
    function getStyle(obj,attr) {
        return obj.currentStyle?obj.currentStyle[attr]:getComputedStyle(obj)[attr];
    }
};