Modifying drag script for drag limit: howto??

**shachi** · 09-17-2006, 03:32 PM

Hello all,
I was playing around this:

Code:

<html>
<head>
<script type="text/javascript">
var ie=document.all;
var nn6=document.getElementById&&!document.all;
var isdrag=false;
var x,y;
var dobj;

function movemouse(e)
{
  if (isdrag)
  {
    dobj.style.left = nn6 ? tx + e.clientX - x : tx + event.clientX - x;
    dobj.style.top  = nn6 ? ty + e.clientY - y : ty + event.clientY - y;
    return false;
  }
}

function selectmouse(e)
{
  var fobj       = nn6 ? e.target : event.srcElement;
  var topelement = nn6 ? "HTML" : "BODY";
  while (fobj.tagName != topelement && fobj.className != "dragme")
  {
    fobj = nn6 ? fobj.parentNode : fobj.parentElement;
  }
  if (fobj.className=="dragme")
  {
    isdrag = true;
    dobj = fobj;
    tx = parseInt(dobj.style.left+0,10);
    ty = parseInt(dobj.style.top+0,10);
    x = nn6 ? e.clientX : event.clientX;
    y = nn6 ? e.clientY : event.clientY;
    document.onmousemove=movemouse;
    return false;
  }
}
document.onmousedown=selectmouse;
document.onmouseup=new Function("isdrag=false");
</script>
<style type="text/css">
.dragme{position:relative;}
#test {
width: 100px;
height: 100px;
background-color: red;
}
</style>
</head>
<body>
<div id="test" class="dragme"></div>
</body>
</html>

drag script and then I thought of something. How do I limit the drag, for example how do I stop the element being dragged from dragging if the element reaches 100px far from the left?? I tried :

Code:

if(!dobj.offsetLeft > 100){
dobj.style.left = nn6 ? tx + e.clientX - x : tx + event.clientX - x;
dobj.style.top = nn6 ? ty + e.clientY - y : ty + event.clientY - y;
} else {
return false;
}

but it doesn't seem to work. Any help here PLEASE!!!!

Thanks.

**mburt** · 09-17-2006, 04:56 PM

Set the onmousemove event handler to null, instead of trying to set the width when the user drags past a certain point.

**shachi** · 09-17-2006, 05:07 PM

Originally Posted by mburt

instead of trying to set the width when the user drags past a certain point.

What do you mean??

**mburt** · 09-17-2006, 05:08 PM

I meant to say (in place of width): the pixels from the left of the screen

Sorry about that.

**shachi** · 09-17-2006, 05:19 PM

mburt: never mind about that but I still can't get what you are trying to say. If I set the onmousemove to null then the drag will stop completely. Here's my code so far(if I understood what you meant).

Code:

<html>
<head>
<script type="text/javascript">
var ie=document.all;
var nn6=document.getElementById&&!document.all;
var isdrag=false;
var x,y;
var dobj;

function movemouse(e){
  if (isdrag){
  if(dobj.offsetLeft < 500){
    dobj.style.left = nn6 ? tx + e.clientX - x : tx + event.clientX - x;
//    dobj.style.top  = nn6 ? ty + e.clientY - y : ty + event.clientY - y;
} else {
document.onmousemove = null;
}
    return false;
  }
}

function selectmouse(e){
  var fobj       = nn6 ? e.target : event.srcElement;
  var topelement = nn6 ? "HTML" : "BODY";
  while (fobj.tagName != topelement && fobj.className != "dragme"){
    fobj = nn6 ? fobj.parentNode : fobj.parentElement;
  }
  if (fobj.className=="dragme"){
    isdrag = true;
    dobj = fobj;
    tx = parseInt(dobj.style.left+0,10);
    ty = parseInt(dobj.style.top+0,10);
    x = nn6 ? e.clientX : event.clientX;
    y = nn6 ? e.clientY : event.clientY;
    document.onmousemove=movemouse;
    return false;
  }
}
document.onmousedown=selectmouse;
document.onmouseup=new Function("isdrag=false");
</script>
<style type="text/css">
.dragme{position:relative;}
#test {
width: 100px;
height: 100px;
background-color: red;
}
</style>
</head>
<body>
<div id="test" class="dragme"></div>
</body>
</html>

**mburt** · 09-17-2006, 05:22 PM

Yes. You want it to stop completely when the value is more or less then the desired value, then you set the "else" statement to:

Code:

document.onmousemove = movemouse;

**shachi** · 09-17-2006, 05:25 PM

mburt: actually that's not what I meant. I need it to stop completely *but* it must be abled to be dragged again. If I set it to document.onmousemove = null it can't be dragged once it exceedes it's limit. Well, let me try what you suggested, here's my code:

Code:

<html>
<head>
<script type="text/javascript">
var ie=document.all;
var nn6=document.getElementById&&!document.all;
var isdrag=false;
var x,y;
var dobj;

function movemouse(e){
  if (isdrag){
  if(dobj.offsetLeft < 500){
    dobj.style.left = nn6 ? tx + e.clientX - x : tx + event.clientX - x;
//    dobj.style.top  = nn6 ? ty + e.clientY - y : ty + event.clientY - y;
} else {
document.onmousemove = mousemove;
}
    return false;
  }
}

function selectmouse(e){
  var fobj       = nn6 ? e.target : event.srcElement;
  var topelement = nn6 ? "HTML" : "BODY";
  while (fobj.tagName != topelement && fobj.className != "dragme"){
    fobj = nn6 ? fobj.parentNode : fobj.parentElement;
  }
  if (fobj.className=="dragme"){
    isdrag = true;
    dobj = fobj;
    tx = parseInt(dobj.style.left+0,10);
    ty = parseInt(dobj.style.top+0,10);
    x = nn6 ? e.clientX : event.clientX;
    y = nn6 ? e.clientY : event.clientY;
    document.onmousemove=movemouse;
    return false;
  }
}
document.onmousedown=selectmouse;
document.onmouseup=new Function("isdrag=false");
</script>
<style type="text/css">
.dragme{position:relative;}
#test {
width: 100px;
height: 100px;
background-color: red;
}
</style>
</head>
<body>
<div id="test" class="dragme"></div>
</body>
</html>

Gives out an error: Error: mousemove is not defined
Source File: ----:///----/------/testdrag.html
Line: 16

**mburt** · 09-17-2006, 05:31 PM

I meant to say:

Code:

document.onmousemove = movemouse

The point is to use whatever your function is for actually moving the object and calling it again.

**mburt** · 09-17-2006, 05:32 PM

I see your point though. I'm not really sure why you wouldn't be able to continue dragging, I'll try to work it out.

**shachi** · 09-17-2006, 05:33 PM

mburt: did you even bother to read the initial code?? The function to move the object *is* movemouse, I apologize if it was a little harsh.

EDIT: You've posted before me.

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