用策略思维做的小球滑动
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<title>Document</title>
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<body>
<div style="position:absolute;background:blue" id="div">我是div</div>
</body>
<script>
var tween = {
linear: function (t, b, c, d) {
return c * t / d + b;
},
easeIn: function (t, b, c, d) {
return c * (t /= d) * t + b;
},
strongEaseIn: function (t, b, c, d) {
return c * (t /= d) * t * t * t * t + b;
},
strongEaseOut: function (t, b, c, d) {
return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
},
sineaseIn: function (t, b, c, d) {
return c * (t /= d) * t * t + b;
},
sineaseOut: function (t, b, c, d) {
return c * ((t = t / d - 1) * t * t + 1) + b;
}
};
var Animate = function (dom) {
this.dom = dom; // 进行运动的dom 节点
this.startTime = 0; // 动画开始时间
this.startPos = 0; // 动画开始时，dom 节点的位置，即dom 的初始位置
this.endPos = 0; // 动画结束时，dom 节点的位置，即dom 的目标位置
this.propertyName = null; // dom 节点需要被改变的css 属性名
this.easing = null; // 缓动算法
this.duration = null; // 动画持续时间
};
Animate.prototype.start = function (propertyName, endPos, duration, easing) {
this.startTime = +new Date; // 动画启动时间
this.startPos = this.dom.getBoundingClientRect()[propertyName]; // dom 节点初始位置
this.propertyName = propertyName; // dom 节点需要被改变的CSS 属性名
this.endPos = endPos; // dom 节点目标位置
this.duration = duration; // 动画持续事件
this.easing = tween[easing]; // 缓动算法
var self = this;
var timeId = setInterval(function () { // 启动定时器，开始执行动画
if (self.step() === false) { // 如果动画已结束，则清除定时器
clearInterval(timeId);
}
}, 16);
};
Animate.prototype.step = function () {
var t = +new Date; // 取得当前时间
if (t >= this.startTime + this.duration) { // (1)
this.update(this.endPos); // 更新小球的CSS 属性值
return false;
}
var pos = this.easing(t - this.startTime, this.startPos, this.endPos - this.startPos, this.duration);
// pos 为小球当前位置
this.update(pos); // 更新小球的CSS 属性值
};
Animate.prototype.update = function (pos) {
this.dom.style[this.propertyName] = pos + 'px';
};
var div = document.getElementById('div');
var animate = new Animate(div);
animate.start('left', 500, 1000, 'linear');
// animate.start( 'top', 1500, 500, 'strongEaseIn' );
</script>
</html>