var nDots = 8; var Xpos = 0; var Ypos = 0; var DELTAT = .01; var SEGLEN = 10; var SPRINGK = 10; var MASS = 1; var GRAVITY = 50; var RESISTANCE = 10;
var STOPVEL = 0.1; var STOPACC = 0.1; var DOTSIZE = 10; var BOUNCE = 0.75; var isNetscape = navigator.appName=="Netscape"; var followmouse = true;
init();
function init()
{ var i = 0; dots = new Array(); for (i = 0; i < nDots; i++) { dots[i] = new dot(i); } if (!isNetscape) { setInitPositions() } 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()", 100); } }
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()
{ var startloc = document.all.tags("LI"); var i = 0; for (i = 0; i < startloc.length; i++) { dots[i+1].X = startloc[i].offsetLeft + startloc[i].offsetParent.offsetLeft; dots[i+1].Y = startloc[i].offsetTop + startloc[i].offsetParent.offsetTop + DOTSIZE/2; } 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; Ypos = window.event.y; } 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; width = window.innerWidth; } else { height = document.body.clientHeight; width = document.body.clientWidth; } 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; } }