Elastic Mouse
With this script you can
make an image follow the mouse cursor as if it where attached to elastic.
Paste The
Following Code into the Body Section of Your Web Page
<div
id="dot0" style="position: absolute; visibility: hidden;
height: 11; width: 11;">
<img src="insert your image name and location here"
height=11 width=11>
</div>
<div id="dot1" style="position: absolute; height:
11; width: 11;">
<img src="insert your image name and location here"
height=11 width=11>
</div>
<div id="dot2" style="position: absolute; height:
11; width: 11;">
<img src="insert your image name and location here"
height=11 width=11>
</div>
<div id="dot3" style="position: absolute; height:
11; width: 11;">
<img src="insert your image name and location here"
height=11 width=11>
</div>
<div id="dot4" style="position: absolute; height:
11; width: 11;">
<img src="insert your image name and location here"
height=11 width=11>
</div>
<div id="dot5" style="position: absolute; height:
11; width: 11;">
<img src="insert your image name and location here"
height=11 width=11>
</div>
<div id="dot6" style="position: absolute; height:
11; width: 11;">
<img src="insert your image name and location here"
height=11 width=11>
</div>
<script
LANGUAGE="JavaScript">
<!-- hide code
var nDots = 7;
var Xpos
= 0;
var Ypos = 0;
// fixed
time step, no relation to real time
var DELTAT = .01;
// size of one spring in pixels
var SEGLEN = 10;
// spring constant, stiffness of springs
var SPRINGK = 10;
// all the physics is bogus, just picked stuff to
// make it look okay
var MASS = 1;
// Positive XGRAVITY pulls right, negative pulls left
// Positive YGRAVITY pulls down, negative up
var XGRAVITY = 0;
var YGRAVITY = 50;
// RESISTANCE determines a slowing force proportional to velocity
var RESISTANCE = 10;
// stopping criterea to prevent endless jittering
// doesn't work when sitting on bottom since floor
// doesn't push back so acceleration always as big
// as gravity
var STOPVEL = 0.1;
var STOPACC = 0.1;
var DOTSIZE = 11;
// BOUNCE is percent of velocity retained when
// bouncing off a wall
var BOUNCE = 0.75;
var isNetscape
= navigator.appName=="Netscape";
// always
on for now, could be played with to
// let dots fall to botton, get thrown, etc.
var followmouse = true;
var dots
= new Array();
init();
function
init()
{
var i = 0;
for (i = 0; i < nDots; i++) {
dots[i] = new dot(i);
}
if (!isNetscape) {
// I only know how to read the locations of the
// <LI> items in IE
//skip this for now
// setInitPositions(dots)
}
// set their positions
for (i = 0; i < nDots; i++) {
dots[i].obj.left = dots[i].X;
dots[i].obj.top = dots[i].Y;
}
if (isNetscape) {
// start right away since they are positioned
// at 0, 0
startanimate();
} else {
// let dots sit there for a few seconds
// since they're hiding on the real bullets
setTimeout("startanimate()", 1000);
}
}
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);
}
// This is to line up the bullets with actual LI tags on the page
// Had to add -DOTSIZE to X and 2*DOTSIZE to Y for IE 5, not sure why
// Still doesn't work great
function setInitPositions(dots)
{
// initialize dot positions to be on top
// of the bullets in the <ul>
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;
}
// put 0th dot above 1st (it is hidden)
dots[0].X = dots[1].X;
dots[0].Y = dots[1].Y - SEGLEN;
}
// just
save mouse position for animate() to use
function MoveHandler(e)
{
Xpos = e.pageX;
Ypos = e.pageY;
return true;
}
// just
save mouse position for animate() to use
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;
}
// adds
force in X and Y to spring for dot[i] on dot[j]
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() {
// dots[0] follows the mouse,
// though no dot is drawn there
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);
}
// air resisitance/friction
var resist = new vec(-dots[i].dx * RESISTANCE,
-dots[i].dy * RESISTANCE);
// compute new accel, including gravity
var accel = new vec((spring.X + resist.X)/MASS + XGRAVITY,
(spring.Y + resist.Y)/ MASS + YGRAVITY);
// compute new velocity
dots[i].dx += (DELTAT * accel.X);
dots[i].dy += (DELTAT * accel.Y);
// stop dead so it doesn't jitter when nearly still
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;
}
// move to new position
dots[i].X += dots[i].dx;
dots[i].Y += dots[i].dy;
// get size of window
var height, width;
if (isNetscape) {
height = window.innerHeight + window.pageYOffset;
width = window.innerWidth + window.pageXOffset;
} else {
height = document.body.clientHeight + document.body.scrollTop;
width = document.body.clientWidth + document.body.scrollLeft;
}
// bounce off 3 walls (leave ceiling open)
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;
}
// move img to new position
dots[i].obj.left = dots[i].X;
dots[i].obj.top = dots[i].Y;
}
}
// end
code hiding -->
</script>