Click to See Complete Forum and Search --> : Turn external script on/off via form/buttons???


jaydb
03-14-2003, 06:01 PM
Hello- Can any of you help me learn how to turn an external script on/off via a form/buttons on a given page?

I have a page, and I would like users to be able to turn on/off script which causes a given mouse-trail effect. I have saved the mouse-trail script as an external script, but I do not know how to create the "run external script" command or function in my webpage.

Thank you for your help!

Jay

Jona
03-14-2003, 06:08 PM
Sure, in the .js file, (open it with Notepad) what is the name of the function? Where it says, "function" and then a word. What is that word and everything inside of the parenthesis? The ( and ).

khalidali63
03-14-2003, 06:45 PM
Originally posted by Jona
Sure, in the .js file, (open it with Notepad) what is the name of the function? Where it says, "function" and then a word. What is that word and everything inside of the parenthesis? The ( and ).

.......gosh..am I having problem understanding....or..??

Cheers

Khalid

Nedals
03-14-2003, 06:46 PM
Better yet, post a link to the web page!

Jona
03-14-2003, 06:48 PM
I guess I wasn't clear.... what's the name of the function in the .js file? That better?

jaydb
03-14-2003, 09:30 PM
Here is the code I found on the internet that does the bouncing trailing mousetrail thing; I would cut out all above the <script> tag and all after the </script> to create the .js file

<HTML>
<HEAD>
<TITLE>Javascript Lab | Bouncing Bullets</TITLE>
</HEAD>

<BODY bgcolor="#FFFFFF" text="#000066" link="#CC6600" vlink="#CC6600" alink="#CC6600">
<div id="dot0" style="position: absolute; visibility: hidden; height: 11; width: 11;"><img src="bullet.gif" height=11 width=11></div>
<div id="dot1" style="position: absolute; height: 11; width: 11;"><img src="bullet.gif" height=11 width=11></div>
<div id="dot2" style="position: absolute; height: 11; width: 11;"><img src="bullet.gif" height=11 width=11></div>
<div id="dot3" style="position: absolute; height: 11; width: 11;"><img src="bullet.gif" height=11 width=11></div>
<div id="dot4" style="position: absolute; height: 11; width: 11;"><img src="bullet.gif" height=11 width=11></div>
<div id="dot5" style="position: absolute; height: 11; width: 11;"><img src="bullet.gif" height=11 width=11></div>
<div id="dot6" style="position: absolute; height: 11; width: 11;"><img src="bullet.gif" height=11 width=11></div>

<P>
<SCRIPT LANGUAGE="JavaScript">

<!-- Begin
var nDots = 7;
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 = 11;
var BOUNCE = 0.75;
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);
}
if (!isNetscape) {
// I only know how to read the locations of the
// <LI> items in IE
//skip this for now
// setInitPositions(dots)
}
for (i = 0; i < nDots; i++) {
dots[i].obj.left = dots[i].X;
dots[i].obj.top = dots[i].Y;
}
if (isNetscape) {
startanimate();
} else {
// let dots sit there for a few seconds
// since they're hiding on the real bullets
setTimeout("startanimate()", 3000);
}
}
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;
}

// 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() {
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;
}
}
// End -->
</script>
<FONT color="#000066" face="Arial, Helvetica, sans-serif" size="3">This page
demonstrates a Javascript special effect using the cursor and a small image.
(bullet.gif: <IMG src="bullet.gif" width="11" height="11">)</FONT></P>
<P>&nbsp;</P>
<P>&nbsp;</P>
<P>&nbsp;</P>
<P>&nbsp;</P>
<P>&nbsp;</P>
<P><FONT face="Arial, Helvetica, sans-serif" size="3"><A href="home.html">JAVASCRIPT
LAB HOME</A></FONT></P>
<P><FONT color="#CC6600" face="Arial, Helvetica, sans-serif" size="3"><A href="../index.html">LAB
HOME</A></FONT></P>
</BODY>

</HTML>

jaydb
03-14-2003, 09:32 PM
so it looks like there are a few differnet functions in the .js file......

Thank you for your help!!!

Jay

Jona
03-14-2003, 09:33 PM
<BODY onload="init()">

jaydb
03-14-2003, 09:38 PM
The demo of the cursor thing and the code can be found here:

http://www.christopherbarth.com/lab/lab_javascripts/bouncing.html

Again, thank you!

Jay

jaydb
03-14-2003, 09:41 PM
Jona, no problem making it run. The issue is, I want visitors to my site to be able to turn the effect on/off via a button or hyperlink.

Can I somehow put a script in my page that says to run the bouncing cursor-trailer external script if user presses "on" button and disables cursor effect of they press an "off" button?

thanks!

Jay

Nedals
03-14-2003, 11:06 PM
This function is the one that runs the animation. What you need to do is stop it on command.

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

Change it to....

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

Now add a function
function stopanimate() {
clearInterval(animate);
return true;
}

Then put a button on your page
<input type="button" value="Stop Animation" onClick="return stopanimate()">

and, if I got that right, it should work.

Jona
03-14-2003, 11:10 PM
What nedals said, only... he said it first.:eek:

jaydb
03-14-2003, 11:56 PM
Nedals, I am in Pleasanton too. Small world. Anyway, sorry to be so helpless - I am new to html and javascript; but I can see how this would stop the animation; but I want a visitor to my page to be able to start the animation by clicking one button, or stop the animation by clicking another button.


Can you tell me how I would do that?

Thank you again.

Jay

jaydb
03-15-2003, 12:10 AM
I tried using the advice but does not work; sure error is on my part. Anyone care to check and see why this is not working?

Here is the code:

<HTML>
<HEAD>
<TITLE>Javascript Lab | Bouncing buttons</TITLE>
</HEAD>

<BODY bgcolor="#FFFFFF" text="#000066" link="#CC6600" vlink="#CC6600" alink="#CC6600">
<div id="dot0" style="position: absolute; visibility: hidden; height: 11; width: 11;"><img

src="button.gif" height=11 width=11></div>
<div id="dot1" style="position: absolute; height: 11; width: 11;"><img

src="button.gif" height=11 width=11></div>
<div id="dot2" style="position: absolute; height: 11; width: 11;"><img

src="button.gif" height=11 width=11></div>
<div id="dot3" style="position: absolute; height: 11; width: 11;"><img

src="button.gif" height=11 width=11></div>
<div id="dot4" style="position: absolute; height: 11; width: 11;"><img

src="button.gif" height=11 width=11></div>
<div id="dot5" style="position: absolute; height: 11; width: 11;"><img

src="button.gif" height=11 width=11></div>
<div id="dot6" style="position: absolute; height: 11; width: 11;"><img

src="button.gif" height=11 width=11></div>

<P>
<SCRIPT LANGUAGE="JavaScript">

<!-- Begin
var nDots = 7;
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 = 11;
var BOUNCE = 0.75;
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);
}
if (!isNetscape) {
// I only know how to read the locations of the
// <LI> items in IE
//skip this for now
// setInitPositions(dots)
}
for (i = 0; i < nDots; i++) {
dots[i].obj.left = dots[i].X;
dots[i].obj.top = dots[i].Y;
}
if (isNetscape) {
startanimate();
} else {
// let dots sit there for a few seconds
// since they're hiding on the real buttons
setTimeout("startanimate()", 3000);
}
}
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() {
animate = setInterval("animate()", 20);
}
function stopanimate() {
clearInterval(animate);
return true;
}
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;
}

// 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() {
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;
}
}
// End -->
</script>
<FONT color="#000066" face="Arial, Helvetica, sans-serif" size="3">This page
demonstrates a Javascript special effect using the cursor and a small image.
(button.gif: <IMG src="button.gif" width="11" height="11"> )</FONT></P>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<P> </P>
<input type="button" value="Stop Animation" onClick="return stopanimate()">


</BODY>

</HTML>

Jona
03-15-2003, 11:52 AM
Try putting the <SCRIPT> in the <HEAD> tag instead of after the images.

Nedals
03-15-2003, 01:07 PM
Would you believe...

<input type="button" value="Start Animation" onClick="return startanimate()">

Nedals
03-15-2003, 03:09 PM
OK!
Here's the problem. When I proposed my solution I had not read through all the code. It turns out that you have a function called 'animate' which is the name I picked for the Interval timer.

So. change as shown...

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

function stopanimate() { clearInterval(timer); return true; }

and no changes needed for the buttons (both)

IN ADDITION, as suggested earlier, move your javascript into the <head> section of your document.

ALSO
Change this 'init();' to, onload = init; // no ()

AND, before you ask, to hide the dots when the animation stops and show then again, use this...

function startanimate() {
timer = setInterval("animate()", 20);
for (i = 0; i < nDots; i++) { dots[i].obj.visibility = 'visible' }
return true;
}

function startanimate() {
timer = setInterval("animate()", 20);
for (i = 0; i < nDots; i++) { dots[i].obj.visibility = 'visible' }
return true;
}

Works in IE (but not netscape)


MINI TUTORIAL:
Always (well, nearly always) put your Javascript (always one word), in the <HEAD> section of your document.
Notable acception: document.write();

jaydb
03-16-2003, 11:41 PM
Thank you for the help!