Draggable layers problem (IE only)

Hi, Folks!

I've been trying to develop my own version of these draggable
layers and I have been limiting myself to IE6...for now. I have
looked at some other examples to get ideas of creating an alternative
to pop-up windows in a web page. The code I have works (sort of).
The problem is that I can move these layers around when I move the
mouse slowly, however, if I move it fast the web browser looses track
of the motion and leaves the layer behind. If anyone has some ideas
or suggestions it would be much appreciated.

TIA

Here's my code:
=======================TEST2.HTM================== ==========

<HTML>

<HEAD>
</HEAD>

<script language="JavaScript" src="DivLayer.js"></script>
<script language="JavaScript" src="DateTime.js"></script>


<div id="Test1" style="position:absolute;width:250px;left:50;top:5 0;visibility:hidden">

<table border=0 width=250 bgcolor=Navy cellspacing=0
cellpadding=5>
<tr>
<td width=100%>
<table border=0 width=100% cellspacing=0 cellpadding=0
height=36>
<tr>

<td id="titleBar" style="cursor:move"
width="100%"
onMouseDown="divTest1.MouseDown();"
onMouseMove="divTest1.MouseMove();"
onMouseUp="divTest1.MouseUp();"
onMouseOut="divTest1.MouseOut();">
<font face=Arial color=#FFFFFF><B><I>Test
1</I></B></font>
</td>

<td id="closeX" style="cursor:hand" valign="top"
onClick="divTest1.ChangeState('hidden');">
<font color=#ffffff size=2 face=arial>
<B>X</B>
</font>
</td>
</tr>
<tr>

<td id="contents" width="100%" bgcolor="#FFFFFF"
style="padding:4px" colspan="2">

This is where your content goes.<br>
It can be any html code or text.<br>
<input type="checkbox" name="myBox"
value="blah">Blah<BR>

</td>
</tr>
</table>
</td>
</tr>
</table>
</div>

<div id="Test2" style="position:absolute;width:400;left:100;top:10 0;visibility:hidden">


<div id="titleBar"
style="cursor:move;padding:1;position:absolute;hei ght:15;width:385;left:0;top:0;background-color:Navy"
onMouseDown="divTest2.MouseDown();"
onMouseMove="divTest2.MouseMove();"
onMouseUp="divTest2.MouseUp();"
onMouseOut="divTest2.MouseOut();">
<font color=#ffffff size=1 face=arial>
<B><I>Test 2</I></B>
</font>
</div>


<div id="closeX"
style="cursor:hand;padding:1;position:absolute;hei ght:15;width:15;left:385;top:0;background-color:Navy"
onClick="divTest2.ChangeState('hidden');">
<font color=#ffffff size=1 face=arial >
<CENTER><B>X</B></CENTER>
</font>
</div>


<div id="contents"
style="position:absolute;width:400;left:0;top:15;p adding:2;background-color:White;border-width:0
1 1 1;border-color:black;border-style:solid">

<select name="lst_ContactList" size="1">
<option>DEFAULT</option>
<option>NOBODY</option>
<option>SOMEBODY</option>
<option>EVERYBODY</option>
<option>ANYBODY</option>
</select>
<BR>
Blah! Blah!<BR>

</div>
</div>

<div id="Test3" style="position:absolute;width:400;left:150;top:12 5;visibility:hidden">


<div id="titleBar"
style="cursor:move;padding:1;position:absolute;hei ght:18;width:382;left:0;top:0;background-color:Navy"
onMouseDown="divTest3.MouseDown();"
onMouseMove="divTest3.MouseMove();"
onMouseUp="divTest3.MouseUp();"
onMouseOut="divTest3.MouseOut();">
<font color=#ffffff size=2 face=arial>
<B><I>Test 3</I></B>
</font>
</div>


<div id="closeX"
style="cursor:hand;padding:1;position:absolute;hei ght:18;width:18;left:382;top:0;background-color:Navy"
onClick="divTest3.ChangeState('hidden');">
<font color=#ffffff size=2 face=arial style="font-weight:bold"[color=blue]
>[/color]
<center>X</center>
</font>
</div>


<div id="contents"
style="position:absolute;width:400;left:0;top:18;p adding:2;background-color:White;border-width:0
1 1 1;border-color:black;border-style:solid">

Main Entry: <b>byte</b> <BR>
Function: <i>noun</i> <BR>
A group of eight binary digits processed as a unit by a
computer and used especially to
represent an alphanumeric character.<br>

</div>
</div>

<div id="Test4" style="position:absolute;width:400;left:200;top:15 0;visibility:hidden">


<div id="titleBar"
style="cursor:move;padding:1;position:absolute;hei ght:20;width:380;left:0;top:0;background-color:Navy"
onMouseDown="divTest4.MouseDown();"
onMouseMove="divTest4.MouseMove();"
onMouseUp="divTest4.MouseUp();"
onMouseOut="divTest4.MouseOut();">
<font color=#ffffff size=3 face=arial>
<B><I>Test 4</I></B>
</font>
</div>


<div id="closeX"
style="cursor:hand;padding:1;position:absolute;hei ght:20;width:20;left:380;top:0;background-color:Navy"
onClick="divTest4.ChangeState('hidden');">
<font color=#ffffff size=3 face=arial style="font-weight:bold"[color=blue]
>[/color]
<center>X</center>
</font>
</div>


<div id="contents"
style="position:absolute;width:400;left:0;top:20;p adding:2;background-color:White;border-width:0
1 1 1;border-color:black;border-style:solid">

Main Entry: <b>byte me</b><BR>
Function: <i>intransitive verb</i> <BR>
An expression used by peaved computers (i.e. the host) where
the current line of queries by other
computers (i.e. the client) leads to annoying the host
computer (e.g. network server).<br>

</div>
</div>

<div id="DateTime" style="position:absolute;width:450;left:200;top:20 0;visibility:hidden">


<div id="titleBar"
style="cursor:move;padding:1;position:absolute;hei ght:18;width:432;left:0;top:0;background-color:Navy"
onMouseDown="divDateTime.MouseDown();"
onMouseMove="divDateTime.MouseMove();"
onMouseUp="divDateTime.MouseUp();"
onMouseOut="divDateTime.MouseOut();">
<font color=#ffffff size=2 face=arial>
<B><I>Pick Time & Date</I></B>
</font>
</div>


<div id="closeX"
style="cursor:hand;padding:1;position:absolute;hei ght:18;width:18;left:432;top:0;background-color:Navy"
onClick="divDateTime.ChangeState('hidden');">
<font color=#ffffff size=2 face=arial style="font-weight:bold"[color=blue]
>[/color]
<center>X</center>
</font>
</div>


<div id="contents"
style="position:absolute;width:450;left:0;top:18;p adding:2;background-color:White;border-width:0
1 1 1;border-color:black;border-style:solid">

<center>
<form name='frm_DateTimeSelect'>
<table border='0'>
<tr>
<td width='50%'>
<p align='center'>
<select name='lst_Month' size='1'></select>
<select name='lst_Date' size='1'></select>
/
<select name='lst_Year' size='1'></select>
</p>
</td>
<td width='25%'>
<p align='center'>
<select name='lst_Hour' size='1'></select>
:
<select name='lst_Minute' size='1'></select>
</p>
</td>
<td width='25%'>
<p align='center'>
<input type='radio' checked name='chk_AMPM'
value='AM'>AM
<input type='radio' name='chk_AMPM' value='PM'>PM
</p>
</td>
</tr>
<tr>
<td colspan='3'>
<p align='center'>
<input type='button' name='btn_OK' value=' OK
' onClick="divDateTime.ChangeState('hidden');saveDat eTime('frm_DateTimeSelect');">
</p>
</td>
</tr>
</table>
</form>
</center>

</div>
</div>

<div id="Date" style="position:absolute;width:350;left:150;top:22 5;visibility:hidden">


<div id="titleBar"
style="cursor:move;padding:1;position:absolute;hei ght:18;width:332;left:0;top:0;background-color:Navy"
onMouseDown="divDate.MouseDown();"
onMouseMove="divDate.MouseMove();"
onMouseUp="divDate.MouseUp();"
onMouseOut="divDate.MouseOut();">
<font color=#ffffff size=2 face=arial>
<B><I>Pick Date</I></B>
</font>
</div>


<div id="closeX"
style="cursor:hand;padding:1;position:absolute;hei ght:18;width:18;left:332;top:0;background-color:Navy"
onClick="divDate.ChangeState('hidden');">
<font color=#ffffff size=2 face=arial style="font-weight:bold"[color=blue]
>[/color]
<center>X</center>
</font>
</div>


<div id="contents"
style="position:absolute;width:350;left:0;top:18;p adding:2;background-color:White;border-width:0
1 1 1;border-color:black;border-style:solid">

<center>
<form name='frm_DateSelect'>
<table border='0'>
<tr>
<td width='50%'>
<p align='center'>
<select name='lst_Month' size='1'></select>
<select name='lst_Date' size='1'></select>
/
<select name='lst_Year' size='1'></select>
</p>
</td>
</tr>
<tr>
<td colspan='3'>
<p align='center'>
<input type='button' name='btn_OK' value=' OK
' onClick="divDate.ChangeState('hidden');saveDate('f rm_DateSelect');">
</p>
</td>
</tr>
</table>
</form>
</center>

</div>
</div>



<script language="JavaScript">

</script>

<BODY>
<a href="javascript:divTest1.ChangeState('visible');" >Show Test 1
Window</a><BR>
<a href="javascript:divTest1.ChangeState('hidden');"> Hide Test 1
Window</a><BR>
<BR>
<a href="javascript:divTest2.ChangeState('visible');" >Show Test 2
Window</a><BR>
<a href="javascript:divTest2.ChangeState('hidden');"> Hide Test 2
Window</a><BR>
<BR>
<a href="javascript:divTest3.ChangeState('visible');" >Show Test 3
Window</a><BR>
<a href="javascript:divTest3.ChangeState('hidden');"> Hide Test 3
Window</a><BR>
<BR>
<a href="javascript:divTest4.ChangeState('visible');" >Show Test 4
Window</a><BR>
<a href="javascript:divTest4.ChangeState('hidden');"> Hide Test 4
Window</a><BR>

<form name="frm_Test">
<p><a href="javascript:divDateTime.ChangeState('visible' );populateDateTimeLists('frm_DateTimeSelect');setD ateOutput('frm_Test.txt_Test1');">Enter
Time & Date: </a>
  <input type="text" name="txt_Test1" size=30></p><BR>
<p><a href="javascript:divDate.ChangeState('visible');po pulateDateLists('frm_DateSelect');setDateOutput('f rm_Test.txt_Test2');">Enter
Date: </a>
  <input type="text" name="txt_Test2" size=30></p><BR>
</form>

<BR>
<BR>
<BR>
<BR>
<BR>
<a href="javascript:ArrayElements()">HTML Elements</a><BR>
<BR>
<iframe name="ifrm_test"></iframe>
</BODY>

</HTML>

======================DIVLAYER.JS================= =========



======================DATETIME.JS================= =========

rdlebreton wrote:
[color=blue]
> The problem is that I can move these layers around when I move the
> mouse slowly, however, if I move it fast the web browser looses track
> of the motion and leaves the layer behind.[/color]

Well, I suppose that if you mouse your pointer too fast, the browser
cannot keep up with positioning the DIV fast enough, so the mouse moves
out of the div... mouseout event -> no more mousemove event:-)

What is usually done is to track the mouse position globally
(document.onmousemove sets global variables indicating the mouse
position), and use this position to drag the element, following the pattern:
- *startDrag*: on document mousedown, you determine if one of the target
in the event flow is to be dragged; if so, you initialize the drag
(pointer, timer) and start the next phase;
- *doDrag*: at regular intervals (using setInterval, or chaining
setTimeout calls), you get the global mouse position and you re-position
your layer accordingly;
- *stopDrag*: on document mouseup, you check whether there was an object
being dragged; if so, you clear the timer (using clearInterval) and
finalize the drag.
[color=blue]
> Here's my code:[/color]

It's far too big! Next time please present a trimmed version,
demonstrating clearly the issue.

Thanks for the suggestion, however...

How is it possible to switch the object in document.onmouseup, onmousedown,
onmouse move?

I tried using that method before and it worked great but only for one
DivLayer. I want to have it set up so that multiple DivLayers are on the
screen and can be moved.

Thanks.

A. Nonymous
(Yeah, yeah. I'm using a different identity.)

"Yann-Erwan Perio" <y-e.perio@em-lyon.com> wrote in message
news:4077275e$0$15670$626a14ce@news.free.fr...[color=blue]
> rdlebreton wrote:
>[color=green]
> > The problem is that I can move these layers around when I move the
> > mouse slowly, however, if I move it fast the web browser looses track
> > of the motion and leaves the layer behind.[/color]
>
> Well, I suppose that if you mouse your pointer too fast, the browser
> cannot keep up with positioning the DIV fast enough, so the mouse moves
> out of the div... mouseout event -> no more mousemove event:-)
>
> What is usually done is to track the mouse position globally
> (document.onmousemove sets global variables indicating the mouse
> position), and use this position to drag the element, following the[/color]
pattern:[color=blue]
> - *startDrag*: on document mousedown, you determine if one of the target
> in the event flow is to be dragged; if so, you initialize the drag
> (pointer, timer) and start the next phase;
> - *doDrag*: at regular intervals (using setInterval, or chaining
> setTimeout calls), you get the global mouse position and you re-position
> your layer accordingly;
> - *stopDrag*: on document mouseup, you check whether there was an object
> being dragged; if so, you clear the timer (using clearInterval) and
> finalize the drag.
>[color=green]
> > Here's my code:[/color]
>
> It's far too big! Next time please present a trimmed version,
> demonstrating clearly the issue.[/color]

A. Nonymous wrote:

[about dragging elements]
[color=blue]
> I tried using that method before and it worked great but only for one
> DivLayer. I want to have it set up so that multiple DivLayers are on the
> screen and can be moved.[/color]

Well, since you're aware of the technique, then it's a conception
problem, but without knowing the specifics of your application, it's
hard to provide you with sound advice.

Here's a simple example (slightly tested only) illustating how to move
several elements at the same time, using (1) a callback function and (2)
a nested structure. However, if your application really requires by
essence to have many objects moved at the same time, then it might be
better to use an intermediate custom-object which would hold the
collection of movable objects, with some possible kind of dynamic
reflection on the HTML.

<style type="text/css">
div{position:absolute;width:100px;height:100px}
div div{left:50px;top:50px;}
div#drgdv0{top:10px;left:10px;background:#f00}
div#drgdv1{top:150px;left:150px;background:#0f0}
div#drgdv2{top:300px;left:300px;background:#00f}
</style>

<script type="text/javascript">
var makeDraggable = (function() {
var allDrgObj=[];
var Mouse={x:0, y:0};
var drgObj=null;

function _e(obj, evt, func){
if(obj[evt]) {
obj[evt]=(function(oldf){
return function(){
func.apply(this, arguments);
return oldf.apply(this, arguments);
}
})(obj[evt]);
} else { obj[evt]=func; }
}

_e(document, "onmousedown",
function(evt) {
var el;
evt=evt||window.event;
for(var el=evt.target||evt.srcElement;el;el=el.parentNode) {
if(el.nodeType==1){
for(var ii=0; ii<allDrgObj.length; ii++){
if(el==allDrgObj[ii].element) {
drgObj=allDrgObj[ii]
startDrag();
return;
}}}}
}
);

_e(document, "onmouseup",
function(evt) { stopDrag(); }
);

_e(document, "onmousemove",
function(evt) {
evt=evt||window.event;
Mouse.x=evt.clientX||evt.pageX||0;
Mouse.y=evt.clientY||evt.pageY||0;
}
);

function startDrag(){
setTimeout(
(function(){
var oldx=Mouse.x, oldy=Mouse.y;
return function(){
if(drgObj){
//asumption here: don't nest your draggable divs
//into absolutely positioned elements,
//or more code is required
var el=drgObj.element,
x=parseInt(el.style.left,10)||el.offsetLeft||0,
y=parseInt(el.style.top,10)||el.offsetTop||0,
offX=Mouse.x-oldx,
offY=Mouse.y-oldy;

el.style.left=(x+offX)+"px";
el.style.top=(y+offY)+"px";
oldx=Mouse.x;
oldy=Mouse.y;

if(typeof drgObj.callback=="function")
drgObj.callback.call(el,{offsetX:offX,offsetY:offY });

setTimeout(arguments.callee, 40);
}
}
})(),
40
);
}

function stopDrag(){ drgObj=null; }

return function (el, cbk){
var d=document;
if(el &&
el.nodeType &&
typeof el.parentNode!="undefined" &&
typeof Function.prototype!="undefined" &&
typeof Function.prototype.apply!="undefined") {
allDrgObj.push({element:el,callback:cbk});
}
}
})();
</script>

<div id="drgdv0"><div style="background:#0ff;"></div></div>
<div id="drgdv1"><div style="background:#f0f;"></div></div>
<div id="drgdv2"><div style="background:#ff0;"></div></div>

<script type="text/javascript">
window.onload=function(evt){
if(document.getElementById){
makeDraggable(document.getElementById("drgdv0"), mngr);
makeDraggable(document.getElementById("drgdv1"), mngr);
makeDraggable(document.getElementById("drgdv2"), mngr);
}
}

function mngr(pos){
for(var div, ii=0; ii<3; ii++){
div=document.getElementById("drgdv"+ii);
if(this.id!=div.id){
div.style.left=
((parseInt(div.style.left,10)||
div.offsetLeft||0)+ii*pos.offsetX)+"px";
div.style.top=
((parseInt(div.style.top,10)||
div.offsetTop||0)+ii*pos.offsetY)+"px";
}
}
}
</script>

Regards,
Yep.

rdlebreton wrote:[color=blue]
> I've been trying to develop my own version of these draggable
> layers and I have been limiting myself to IE6...for now.[/color]

IE is probably one of the worst browsers to do primary development on.
It is so error tolerant, and supports so many non-standard methods that
what works on IE often will not work on browsers that are actually
equally dynamic and capable (at least in the area of DHTML). Working
with IE may tend to give the script author the impression that it is a
lot of work to create cross-browser scripts, while developing on a
browser that implements W3C DOM standard methods, but is intolerant of
errors, will usually result in code that also works on IE, along with
all other browsers that implement those methods.
[color=blue]
> I have
> looked at some other examples to get ideas of creating an alternative
> to pop-up windows in a web page. The code I have works (sort of).
> The problem is that I can move these layers around when I move the
> mouse slowly, however, if I move it fast the web browser looses track
> of the motion and leaves the layer behind.[/color]

Yep has already pointed out why that happens. It is rarely possible to
animate a DIV sufficiently quickly or accurately to genuinely follow
mouse movements over that DIV. Instead following mouse movements at the
document level is more practical, but mouse movements events at that
level are to quick to allow any animation to directly follow from those
events, so the actual animation has to be done by a method that uses
setTimeout or setInterval.
[color=blue]
> If anyone has some ideas
> or suggestions it would be much appreciated.[/color]

Well, suggestions must include more considered z-index handling. And
positioning DIVs that contain form controls suffers from the problem
that some controls cannot be covered by a DIV on some browsers, which
suggests that DIVs such controls might some measure to hide those
controls when their DIV is covered with another, so some sort of
detection of overlapping DIVs.

<snip>[color=blue]
> <script language="JavaScript" src="DivLayer.js"></script>[/color]

Valid Html 4 requires opening script tags to include a type attribute,
which, once provided, renders the deprecated language attribute
redundant.
[color=blue]
> <script language="JavaScript" src="DateTime.js"></script>[/color]

The Date script does not appear to have any baring on the problem.

<snip>[color=blue]
> <td id="titleBar" style="cursor:move"[/color]
<snip>[color=blue]
> <div id="titleBar"[/color]
<snip>[color=blue]
> <div id="titleBar"[/color]
<snip>

ID attributes are supposed to be unique within a document.

Recently I have been investigating using DIVs as an alternative for
tasks that are often attempted with new windows (because of the
irresolvable pop-up blocking problem) so I thought I would have a look
at your script, and have a go at re-implementing it to do what you
wanted. The results are to big to post so I have made them available
on-line at:-

<URL: http://www.litotes.demon.co.uk/examp...iWindow_1.html[color=blue]
>[/color]
(Note: don't expect this file to be available for more than a week or
two.)

- it could still stand some more work, and more general testing (I have
only tired it with windows versions of Opera, Mozilla and IE so far) but
might be worth a look.

Richard.

1st reaction:

I like what you've done with the code. You've practically done
everything I was trying to do.

2nd reaction:

Wow! That's a lot of code and a lot more about JavaScript that I don't
understand. It is going to take me a while to wrap my brain around that.

This was really for an Intranet site. Everyone here uses IE but
learning the in's and out's of NN and Opera I'm sure is a good thing. I
kept looking and looking at different examples of draggable layers and could
not wrap my brain around them because they were so complex. I kept thinking
there has GOT to be an easier way to do this (e.g. avoiding
document.onMouseMove, etc). Obviously, I was wrong.

"Richard Cornford" <Richard@litotes.demon.co.uk> wrote in message
news:c5f3hk$n7i$1$8300dec7@news.demon.co.uk...

<big snip>
[color=blue]
> <URL: http://www.litotes.demon.co.uk/examp...iWindow_1.html[color=green]
> >[/color]
> (Note: don't expect this file to be available for more than a week or
> two.)
>
> - it could still stand some more work, and more general testing (I have
> only tired it with windows versions of Opera, Mozilla and IE so far) but
> might be worth a look.
>
> Richard.
>
>[/color]

Just as a foot note:

I have added onSelectStart = "return false;" to the titleBar in my example
and that seems to clean up some of the strange behaviour. However, using
the document.onmousemove, up, down, etc. would be the best way to go because
the animation / moving is cleaner...I just can't wrap my brain around that
code right now.

:P

A. Nonymous wrote:
[color=blue]
> I just can't wrap my brain around that
> code right now.[/color]

Javascript can be coded in different flavors, and Richard's using at
perfection a particular coding style which is very powerful, but
(unfortunately) not well known - closures-based style. As such, it can
be quite obscure when you encounter it the first time.

An excellent introduction has been written recently by Mr Cornford on
this subject; though quite technical, it is well-structured and
detailed. If I may suggest, give it a chance; you'll probably find some
useful analytical axis which could help you into understanding the
script he's provided.

<URL:http://www.jibbering.com/faq/faq_notes/closures.html>

Regards,
Yep.

On Mon, 12 Apr 2004 23:00:19 +0100, "Richard Cornford"
<Richard@litotes.demon.co.uk> wrote:
[color=blue]
><URL: http://www.litotes.demon.co.uk/examp...iWindow_1.html[color=green]
>>[/color]
>(Note: don't expect this file to be available for more than a week or
>two.)[/color]

Feel free to use http://jibbering.com/2004/04/etc. (as you have a log
in anyway) if you want to maintain things longer, I'm also willing to
create a js.jibbering.com or similar for maintaining resources.

I feel it's important that things mentioned have legs!

Jim.
--
comp.lang.javascript FAQ - http://jibbering.com/faq/

Draggable layers problem (IE only)

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re: Draggable layers problem (IE only)

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/bytes/development

/bytes/it

/bytes/about