/*Elastic Trail script (By Philip Winston @ pwinston@yahoo.com)Thanks to Troels Jakobsen <tjak@get2net.dk>*/
var nDots = 4;
if (document.all&&window.print)
document.body.style.cssText="overflow-x:hidden;overflow-y:scroll"
var Xpos = 10;
var Ypos = 0;
var DELTAT = .01;
var SEGLEN = 20;
var SPRINGK = 10;
var MASS = 3;
var GRAVITY = 5;
var RESISTANCE = 25;
var STOPVEL = 0.1;
var STOPACC = 0.1;
var DOTSIZE = 11;
var BOUNCE = 0.9;
var isNetscape = navigator.appName=="Netscape";
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;dots[i].obj.top = dots[i].Y;}
    if (isNetscape) startanimate(); else setTimeout("startanimate()", 2000);
}
function dot(i) 
{
    this.X = Xpos;
    this.Y = Ypos;
    this.dx = 0;
    this.dy = 0;
    if (isNetscape) this.obj = eval("document.dot" + i); else this.obj = eval("dot" + i + ".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){
    Xpos = e.pageX;
    Ypos = e.pageY;       
    return true;
}
function MoveHandlerIE(){
    Xpos = window.event.x + document.body.scrollLeft;
    Ypos = window.event.y + document.body.scrollTop;      
}
if (isNetscape) {
    document.captureEvents(Event.MOUSEMOVE);
    document.onMouseMove = MoveHandler;
} else document.onmousemove = MoveHandlerIE;
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 = Xpos;
        dots[0].Y = Ypos;       
        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,(spring.Y + resist.Y)/ MASS + GRAVITY);
        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 (isNetscape) {
            height = window.innerHeight + document.scrollTop;
            width = window.innerWidth + document.scrollLeft;
        } else {        
            height = document.body.clientHeight + document.body.scrollTop;
            width = document.body.clientWidth + document.body.scrollLeft;
        }
        if (dots[i].Y >=  height - DOTSIZE - 1) {
            if (dots[i].dy > 0) {
                dots[i].dy = BOUNCE * -dots[i].dy;
            }
            dots[i].Y = height - DOTSIZE - 1;
        }
        if (dots[i].X >= width - DOTSIZE) {
            if (dots[i].dx > 0) {
                dots[i].dx = BOUNCE * -dots[i].dx;
            }
            dots[i].X = width - DOTSIZE - 1;
        }
        if (dots[i].X < 0) {
            if (dots[i].dx < 0) {
                dots[i].dx = BOUNCE * -dots[i].dx;
            }
            dots[i].X = 0;
        }
        dots[i].obj.left = dots[i].X;                   
        dots[i].obj.top =  dots[i].Y;           
    }
}