Javascript implementation of gravity bouncing drag movement effect example_javascript skills

Demo address:
http://www.ihuxu.com/project/gcdmove/

Calling example:
var GCDM = gcdMove(oDiv ,100,0);
GCDM.startMove();//Start movement
GCDM.stopMove();//End movement
This JS code has been encapsulated, the code is as follows:
Brief description - obj is the object element to be changed, usually a certain div; iSpeedX and iSpeedY are the initial speed of the horizontal (right) and vertical (bottom) directions of the div. Of course, they can also be set to zero.

Copy code The code is as follows:

/**
* @Desc Gravity Crash Drag Move(gcdMove)
* @Author GenialX
* @URL www.ihuxu.com
* @QQ 2252065614
* @Date 2013.06.22
*/
function gcdMove(obj, iSpeedX, iSpeedY) {
_this = this;//public identifier
//construct fun
var gcdMove;
//self defined fun
var start;
_this.startMove;
//other var
var iTimer;
var iLastX = 0;
var iLastY = 0;
//construct fun
start = function() {
clearInterval(iTimer);
iTimer = setInterval(function() {
iSpeedY = 3;
var l = obj.offsetLeft iSpeedX;
var t = obj.offsetTop iSpeedY;
if (t >= document.documentElement.clientHeight - obj.offsetHeight) {
iSpeedY *= -0.8;
iSpeedX *= 0.8;
t = document.documentElement.clientHeight - obj.offsetHeight;
} else if (t <= 0) {
iSpeedY *= -1;
iSpeedX *= 0.8;
t = 0;
}
if (l >= document.documentElement.clientWidth - obj.offsetWidth) {
iSpeedX *= -0.8;
l = document.documentElement.clientWidth - obj.offsetWidth;
} else if (l <= 0) {
iSpeedX *= -0.8;
l = 0;
}
if (Math.abs(iSpeedX) < 1) {
iSpeedX = 0;
}
if (iSpeedX == 0 && iSpeedY == 0 && t == document.documentElement.clientHeight - obj.offsetHeight) {
clearInterval(iTimer);
}
obj.style.left = l 'px' ;
obj.style.top = t 'px';
}, 30);
}
_this.startMove = function(){
obj.onmousedown = function(ev) {
clearInterval(iTimer);
var oEvent = ev || event;
var disX = oEvent.clientX - obj.offsetLeft;
var disY = oEvent.clientY - obj.offsetTop;
document.onmousemove = function(ev) {
var oEvent = ev || event;
var l = oEvent.clientX - disX;
var t = oEvent.clientY - disY;
obj.style .left = l 'px';
obj.style.top = t 'px';
if(iLastX ==0){
iLastX = l;
}
if(iLastY == 0){
iLastY = t;
}
iSpeedX = l - iLastX;
iSpeedY = t - iLastY;
iLastX = l;
iLastY = t;
}
}
obj.onmouseup = function() {
document.onmousedown = null;
document.onmousemove = null;
document.onmouseup = null;
start() ;
}
start();
}
_this.stopMove = function(){
clearInterval(iTimer);
obj.onmousedown = null;
document.onmousemove = null;
obj.onmouseup = null;
iLastX = 0;
iLastY = 0;
iSpeedX = 0;
iSpeedY = 0;
disX = 0;
disY = 0;
}
//CONSTRUCT AREA
var gcdMove = function() {
if (!iSpeedX) {
iSpeedX = 0;
}
if ( !iSpeedY) {
iSpeedY = 0;
}
}
gcdMove();
}