mouse verfolger

[bo]

hi!

ich hab ein Problem. im moment benutze ich für ein paar bälle die den mauszeiger verfolgen (über den sinn lässt sich streiten, aber bite nicht hier), folgendes script (nicht von mir):

var nDots = 7; if (document.all&&window.print) document.body.style.cssText="overflow-x:hidden;overflow-y:scroll" 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; var GRAVITY = 50; 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()", 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); }

// This is to line up the bullets with actual LI tags on the page // Had to add -DOTSIZE to X and 2DOTSIZE 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 + 2DOTSIZE;     }     // 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(dxdx + dydy);     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,             (spring.Y + resist.Y)/ MASS + GRAVITY);

// 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 + document.scrollTop;             width = window.innerWidth + document.scrollLeft;         } else {             height = document.body.clientHeight + document.body.scrollTop;             width = document.body.clientWidth + document.body.scrollLeft;         }

// bounce of 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;     } }

dazu kommt noch im body-bereich:

<div id='dot0' style='position: absolute; visibility: hidden; height: 11; width: 11;'><img src='blauer_ball.gif' height=11 width=11></div> <div id='dot1' style='position: absolute; height: 11; width: 11;'><img src='blauer_ball.gif' height=11 width=11></div> <div id='dot2' style='position: absolute; height: 11; width: 11;'><img src='blauer_ball.gif' height=11 width=11></div> <div id='dot3' style='position: absolute; height: 11; width: 11;'><img src='blauer_ball.gif' height=11 width=11></div> <div id='dot4' style='position: absolute; height: 11; width: 11;'><img src='blauer_ball.gif' height=11 width=11></div> <div id='dot5' style='position: absolute; height: 11; width: 11;'><img src='blauer_ball.gif' height=11 width=11></div> <div id='dot6' style='position: absolute; height: 11; width: 11;'><img src='blauer_ball.gif' height=11 width=11></div>

das entsprechende bild dazu (blauer_ball.gif) unten...

nun will ich dieses script nicht automatisch starten lassen, sondern per klick des user (per link, bzw. OnClick="blabla()") leider klappt das so nicht, hat einer eine idee wie ich das machen könte?

[bo]

um es klarzustellen: ich brauche kein neues script, sondern einfach nur eine einfache möglichkeit es per aufruf starten zu lassen.

[Peter]

Hallo,

Lass die Funktion 'startanimate()' nicht automatisch starten
sondern leg sie auf einen Link.

mfg,
Peter