详细讲解一下里面的代码，这是一个js的缩放

var imgs = document.getElementsByClassName("i");
for (var i = 0; i < imgs.length; i++) {
imgs[i].onmouseover = function () {
startMov(this, { width: 150, height: 200, top: 0, left: 0 });
}

imgs[i].onmouseout = function () {
    startMov(this, { width: 200, height: 450, top: -16, left: -150 });
}
//设置图像计时器为空值
imgs[i].timer = null;

}
function startMov(element, styles) {
clearInterval(element.timer);
element.timer = setInterval(function () {
for (var attr in styles) {
var icur = 0;
if (attr == 'width') {
icur = Math.round(parseFloat(getStyle(element, attr)) * 100);
} else{
icur = parseInt(getStyle(element, attr));
}

        var speed = 0;
        speed = (styles[attr] - icur) / 8;
        speed = speed > 0 ? Math.ceil(speed) : Math.floor(speed);
        if (attr == 'width') {
            element.style.width = (icur + speed) / 100;
        } else {
            element.style[attr] = icur + speed + 'px';
        }
    }
}, 30);

}
function getStyle(obj, attr) {
if (obj.currentStyle) {
return obj.currentStyle[attr]; //仅限IE兼容
} else {
return getComputedStyle(obj, false)[attr]; //兼容FF
}
}

哪块看不懂