运动五 ---- 训练逻辑思维第五步

function sport_05(obj,attr,target){
clearInterval(obj.timer);
obj.timer = setInterval(()=>{
//当前值
var cur = parseInt(getStyle(obj,attr));
let speed = (target - cur) / 8; //基数
speed = speed > 0 ? Math.ceil(speed) : Math.floor(speed);
if(cur === target){
clearInterval(obj.timer);
}else{
obj.style.width = cur + speed + ‘px’;
}
},30)
}

//获取非行内样式
function getStyle(obj,attr){
return obj.currentStyle ? obj.currentStyle[attr] : getComputedStyle(obj,true)[attr];
}