Cursor with effects Javascript

var nDots = 9; // Число элементов шлейфа +1
var Xbpos = 0;
var Ybpos = 0;

var DELTAT = .01;
var SEGLEN = 10;
var SPRINGK = 10;
var MASS = 1;
var XGRAVITY = 0;
var YGRAVITY = 50;
var RESISTANCE = 10;
var STOPVEL = 0.1;
var STOPACC = 0.1;
var DOTSIZE = 11;
var BOUNCE = 0.75;
var followmouse = true;
var dots = new Array();

init();

function init()
{
var i = 0;
for (i = 0; i < nDots; i++) { dots[i] = new dot(i); } for (i = 0; i < nDots; i++) { dots[i].obj.left = dots[i].X + "px"; dots[i].obj.top = dots[i].Y + "px"; } setTimeout("startanimate()", 10); } function dot(i)
{
this.X = Xbpos;
this.Y = Ybpos;
this.dx = 0;
this.dy = 0;

var id = "adot" + i;
var elem = document.getElementById(id);
this.obj = elem.style;
}

function startanimate()
{
setInterval("animate()", 20);
}

function setInitPositions(dots)
{
var startloc = document.all.tags("Li");
var i = 0;
for (i = 0; i < startloc.length && i < (nDots - 1); i++) { dots[i+1].X = startloc[i].offsetLeft + startloc[i].offsetParent.offsetLeft - DOTSIZE; dots[i+1].Y = startloc[i].offsetTop + startloc[i].offsetParent.offsetTop + 2*DOTSIZE; } dots[0].X = dots[1].X; dots[0].Y = dots[1].Y - SEGLEN; } function MoveHandler(e)
{
if (window.event)
{
Xbpos = window.event.x + document.body.scrollLeft;
Ybpos = window.event.y + document.body.scrollTop;
}
else
{
Xbpos = e.pageX;
Ybpos = e.pageY;
return true;
}
}

document.onmousemove = MoveHandler;

function vec(X, Y)
{
this.X = X;
this.Y = Y;
}

function springForce(i, j, spring)
{
var dx = (dots[i].X - dots[j].X);
var dy = (dots[i].Y - dots[j].Y);
var len = Math.sqrt(dx*dx + dy*dy);
if (len > SEGLEN)
{
var springF = SPRINGK * (len - SEGLEN);
spring.X += (dx / len) * springF;
spring.Y += (dy / len) * springF;
}
}

function animate()
{
var start = 0;
if (followmouse)
{
dots[0].X = Xbpos;
dots[0].Y = Ybpos;
start = 1;
}

for (i = start ; i < nDots; i++ ) { var spring = new vec(0, 0); if (i > 0)
{
springForce(i-1, i, spring);
}
if (i < (nDots - 1)) { springForce(i+1, i, spring); } var resist = new vec(-dots[i].dx * RESISTANCE, -dots[i].dy * RESISTANCE);
var accel = new vec((spring.X + resist.X)/MASS + XGRAVITY, (spring.Y + resist.Y)/ MASS + YGRAVITY);

dots[i].dx += (DELTAT * accel.X);
dots[i].dy += (DELTAT * accel.Y);

if (Math.abs(dots[i].dx) < STOPVEL && Math.abs(dots[i].dy) < STOPVEL && Math.abs(accel.X) < STOPACC && Math.abs(accel.Y) < STOPACC) { dots[i].dx = 0; dots[i].dy = 0; } dots[i].X += dots[i].dx; dots[i].Y += dots[i].dy; var height, width;
if (typeof window.innerWidth != 'undefined')
{
width = window.innerWidth + window.pageXOffset;
height = window.innerHeight + window.pageYOffset;
}
else
if (typeof document.documentElement != 'undefined' && typeof document.documentElement.clientWidth != 'undefined' && document.documentElement.clientWidth != 0)
{
width = document.documentElement.clientWidth + document.body.scrollLeft;
height = document.documentElement.clientHeight + document.body.scrollTop;
}
else
{
width = document.getElementsByTagName('body')[0].clientWidth + document.body.scrollLeft;
height = document.getElementsByTagName('body')[0].clientHeight + document.body.scrollTop;
}