JavaScript Reorderlist

Jassem Abdal, 22 Aug 2007

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Reorderlist using JavaScript that allows dragging between lists

Screenshot - reorderlist1.gif

Introduction

I was playing around with the Microsoft AJAX Reorderlist control and I wanted to be able to drag items between the 2 Reorderlists. I realized this wasn't going to happen any time soon unless I wrote it myself in JavaScript.

Background

To create this kind of functionality, I decided to use a container div with divs inside representing the items to reorder. I used DOM to maneuver the divs appropriately based on jscript mouse dragging events (ondragstart, ondrag, ondragover, ondrop). I checked the Y-axis position of the mouse cursor inside the container div against all of its child divs' Y-axis positions (plus half the child's height) to determine where the dragged div should go. If the mouse cursor position is outside of a container div when ondrop is fired, the child div's original placement is restored. Currently, it only works for IE because I haven't looked into FF mouse dragging events yet.

Using the Code

Just copy and paste this into an HTML file to run it.

<head>
<script type="text/javascript">

var divFollow, divPreview, divDrag, divMove, divParent, divBefore, 
    divAfter, mouseX, mouseY, halfY, isInDiv;

function debug(s)
{
  document.getElementById("debug").innerHTML=s;
}

function getMouseX(e) 
{
    return e.pageX
        || ( e.clientX+(document.documentElement.scrollLeft
        || document.body.scrollLeft));
}

function getMouseY(e) 
{
    return e.pageY
        || (e.clientY+(document.documentElement.scrollTop
        || document.body.scrollTop));
}

function childDragStart(obj,e)
{
    divDrag=obj;
    divBefore=null;
    divAfter=null;
    divBefore=divDrag.previousSibling;
    divAfter=divDrag.nextSibling;
}

function childDrag(obj,e)
{
    mouseX=getMouseX(e);
    mouseY=getMouseY(e);
    divFollow.innerHTML=obj.innerHTML;
    halfY=divFollow.offsetHeight/2;
    divFollow.style.left=mouseX+15;
    divFollow.style.top=mouseY-halfY;
  
    if((mouseY>divParent.offsetTop+divParent.offsetHeight) 
        ||(mouseX>divParent.offsetLeft+divParent.offsetWidth)
        ||(mouseY<divParent.offsetTop)
        ||(mouseX<divParent.offsetLeft)) isInDiv=false;
    else isInDiv=true;
  
    for(var i=0;divParent.childNodes[i];i++)
    {
        node=divParent.childNodes[i];
       if(mouseY-divParent.offsetTop < (node.offsetHeight/2)+node.offsetTop)
        {    
            divParent.insertBefore(divPreview,divParent.childNodes[i]);
            return;    
        }
    }    
    divParent.appendChild(divPreview);
}

function parentDragOver(obj,e)
{
    divParent=obj;
}

function parentDrop(obj,e)
{ 
    var p=document.getElementById("divPreview");
    var n;
    if(divDrag && isInDiv)
    {
        if(p)
        {
            divParent.insertBefore(divDrag,p);            
            divParent.removeChild(p);            
            divDrag=null;
        }
    }
    else if(divDrag)
    {
        //restore original position
        n=divDrag.parentNode;
        if(divAfter) n.insertBefore(divDrag,divAfter);
        else n.appendChild(divDrag);
        divDrag=null;
        if(p) divParent.removeChild(p);
    }
    divFollow.style.left=-1000;
    divFollow.style.top=-1000;
    divDrag=null;
}

//do some initialization.
function initReorderlists(page)
{
    eventpage=page; //page to pass reorderlist events to.
    divDrag=null;
  
    divFollow=document.createElement("div");
    divFollow.style.border="1px solid black";
    divFollow.style.color="black";
    divFollow.style.fontWeight="bold"
    divFollow.backgound="transparent";
    divFollow.id="divFollow";
    divFollow.style.position="absolute";
    divFollow.style.left=-1000;
    divFollow.style.top=-1000;
    document.body.appendChild(divFollow);
  
    divPreview=document.createElement("div");
    divPreview.innerHTML=" ";
    divPreview.style.color="red";
    divPreview.backgound="transparent";
    divPreview.id="divPreview";
    divPreview.style.border="1px dotted black";  
}
</script>
</head>

<body onload="initReorderlists()">

<div ondragover="parentDragOver(this,event)" 
    ondragend="parentDrop(this,event)" id="div1" 
    style="border:1px solid black;width:300px">
    <div><img ondrag="childDrag(this.parentNode,event);" 
        ondragstart="childDragStart(this.parentNode,event);" 
        src="drag.gif"/>div1 child1</div>
    <div><img ondrag="childDrag(this.parentNode,event);" 
        ondragstart="childDragStart(this.parentNode,event);" 
        src="drag.gif"/>div1 child2</div>
    <div><img ondrag="childDrag(this.parentNode,event);" 
        ondragstart="childDragStart(this.parentNode,event);" 
        src="drag.gif"/>div1 child3</div>
    <div><img ondrag="childDrag(this.parentNode,event);" 
        ondragstart="childDragStart(this.parentNode,event);" 
        src="drag.gif"/>div1 child4</div>
    <div><img ondrag="childDrag(this.parentNode,event);" 
        ondragstart="childDragStart(this.parentNode,event);" 
        src="drag.gif"/>div1 child5</div>
</div>

<div ondragover="parentDragOver(this,event)" 
    ondragend="parentDrop(this,event)" id="div2" 
    style="border:1px solid black;width:300px">
    <div><img ondrag="childDrag(this.parentNode,event);" 
        ondragstart="childDragStart(this.parentNode,event);" 
        src="drag.gif"/>div2 child1</div>
    <div><img ondrag="childDrag(this.parentNode,event);" 
        ondragstart="childDragStart(this.parentNode,event);" 
        src="drag.gif"/>div2 child2</div>
    <div><img ondrag="childDrag(this.parentNode,event);" 
        ondragstart="childDragStart(this.parentNode,event);" 
        src="drag.gif"/>div2 child3</div>
    <div><img ondrag="childDrag(this.parentNode,event);" 
        ondragstart="childDragStart(this.parentNode,event);" 
        src="drag.gif"/>div2 child4</div>
    <div><img ondrag="childDrag(this.parentNode,event);" 
        ondragstart="childDragStart(this.parentNode,event);" 
        src="drag.gif"/>div2 child5</div>
</div>

<div id="debug"></div>

</body>

History

22 August, 2007 -- Rewritten to use ondrag* events instead of onmouse* events
17 August, 2007 -- Original version posted

License

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