重力效果v1.0

 主要代码：

 1 function gravity() {
 2     this.init();
 3     this.speedY = 0;
 4     this.clientY = this.getViewport().height;
 5 }
 6 gravity.prototype = {
 7     init: function () {
 8         var newDiv = document.createElement("div");
 9         newDiv.id = "box";
10         var newImg = document.createElement("img");
11         newImg.src = "apple.png";
12         newDiv.appendChild(newImg);
13         document.body.appendChild(newDiv);
14 
15         var _this = this;
16         this.addHandler(newDiv, "click", function () {
17             setInterval(function () { _this.shake(newDiv) }, 30);
18         });
19     },
20 
21     shake: function (oBox) {
22         this.speedY += 2;
23         var t = oBox.offsetTop + this.speedY;
24         if (t > this.clientY - oBox.offsetHeight) {
25             t = this.clientY - oBox.offsetHeight;
26             this.speedY *= -1;
27             this.speedY *= 0.75;
28             this.speedY = Math.round(this.speedY);
29         }
30         else if (t < 0) {
31             t = 0;
32             this.speedY *= -1;
33             this.speedY *= 0.75;
34             this.speedY = Math.round(this.speedY);
35         }
36         oBox.style.top = t + 'px'
37     },
38     getViewport: function () {
39         if (document.compatMode == "BackCompat") {
40             return {
41                 width: document.body.clientWidth,
42                 height: document.body.clientHeight
43             };
44         }
45         else {
46             return {
47                 width: document.documentElement.clientWidth,
48                 height: document.documentElement.clientWidth
49             };
50         }
51     },
52     addHandler: function (element, type, handler) {
53         if (element.addEventListener) {
54             element.addEventListener(type, handler, false);
55         }
56         else if (element.attachEvent) {
57             element.attachEvent("on" + type, handler);
58         }
59         else {
60             element["on" + type] = handler;
61         }
62     },
63 
64     removeHandler: function (element, type, handler) {
65         if (element.removeEventListener) {
66             element.removeEventListener(type, handler, false);
67         }
68         else if (element.detachEvent) {
69             element.detachEvent("on" + type, handler);
70         }
71         else {
72             element["on" + type] = null;
73         }
74     }
75 }

 

/Files/MasterHeng/重力效果.zip