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I'm looking for someone to explain how to drag and drop in javascript, I want a horizontal line with some customizable images in it.

I've had a look at the online tutorials for these but find them very hard to use.

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  • How can you put an image in a line ? How can you put a shape in a line ? Can you be more explicit ? Thanks
    – schlebe
    Commented May 19, 2020 at 12:50

4 Answers 4

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5

I would recommend that you look into one of the Javascript Frameworks out there. We use prototype with scriptaculous.

You can look at a demo for Drag and Drop in Scriptaculous here. And you can run through a tutorial here.

Or look into any of the other frameworks such as JQuery or Dojo.

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3

Here is my code as it is...I have used this page to get this far..

It currently moves everything into column one, I think it's something to do with the mouse.

print("<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>


<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Page</title>
<--
<style type="text/css">
<!--
.DragContainer, .OverDragContainer {
  float: left;
  margin: 3px;
  width: 100px;
  border: #669999 2px solid;
  padding: 5px;
}

.DragBox, .OverDragBox, .DragDragBox, .miniDragBox {
  border: #000 1px solid;
  padding: 2px;
  font-size: 10px;
  margin-bottom: 5px;
  width: 94px;
  cursor: pointer;
  font-family: verdana, tahoma, arial;
  background-color: #eee;
}

.OverDragContainer {
    background-color: #eee;
}

.OverDragBox, .DragDragBox {
  background-color: #ffff99;
}

.DragDragBox {
  filter: alpha(opacity=50);
  background-color: #ff99cc;
}

legend {
  font-weight: bold;
  font-size: 12px;
  color: #666699;
  font-family: verdana, tahoma, arial;
}

fieldset {
  padding: 3px;
}

.History {
  font-size: 10px;
  overflow: auto;
  width: 100%;
  font-family: verdana, tahoma, arial;
  height: 82px;
}

#DragContainer8 {
  border: #669999 1px solid;
  padding: 5px 0 0 5px
  width: 110px;
  height: 40px;
}

.miniDragBox {
  float: left;
  margin: 0 5px 5px 0;
  width: 20px;
  height: 20px;
}
-->
</style>
<--script type="text/javascript">

// iMouseDown represents the current mouse button state: up or down
/*
lMouseState represents the previous mouse button state so that we can
check for button clicks and button releases:

if(iMouseDown && !lMouseState) // button just clicked!
if(!iMouseDown && lMouseState) // button just released!
*/
var mouseOffset = null;
var iMouseDown  = false;
var lMouseState = false;
var dragObject  = null;

// Demo 0 variables
var DragDrops   = [];
var curTarget   = null;
var lastTarget  = null;
var dragHelper  = null;
var tempDiv     = null;
var rootParent  = null;
var rootSibling = null;

Number.prototype.NaN0=function(){return isNaN(this)?0:this;}

function CreateDragContainer(){
    /*
    Create a new "Container Instance" so that items from one "Set" can not
    be dragged into items from another "Set"
    */
    var cDrag        = DragDrops.length;
    DragDrops[cDrag] = [];

    /*
    Each item passed to this function should be a "container".  Store each
    of these items in our current container
    */
    for(var i=0; i<arguments.length; i++){
        var cObj = arguments[i];
        DragDrops[cDrag].push(cObj);
        cObj.setAttribute('DropObj', cDrag);

        /*
        Every top level item in these containers should be draggable.  Do this
        by setting the DragObj attribute on each item and then later checking
        this attribute in the mouseMove function
        */
        for(var j=0; j<cObj.childNodes.length; j++){

            // Firefox puts in lots of #text nodes...skip these
            if(cObj.childNodes[j].nodeName=='#text') continue;

            cObj.childNodes[j].setAttribute('DragObj', cDrag);
        }
    }
}

function getMouseOffset(target, ev){
    ev = ev || window.event;

    var docPos    = getPosition(target);
    var mousePos  = mouseCoords(ev);
    return {x:mousePos.x - docPos.x, y:mousePos.y - docPos.y};
}

function getPosition(e){
    var left = 0;
    var top  = 0;

    while (e.offsetParent){
        left += e.offsetLeft;
        top  += e.offsetTop;
        e     = e.offsetParent;
    }

    left += e.offsetLeft;
    top  += e.offsetTop;

    return {x:left, y:top};
}



function makeDraggable(item){
    if(!item) return;
    item.onmousedown = function(ev){
        dragObject  = this;
        mouseOffset = getMouseOffset(this, ev);
        return false;
    }
}

function makeClickable(object){
    object.onmousedown = function(){
        dragObject = this;
    }
}

function mouseCoords(ev){
    if(ev.pageX || ev.pageY){
        return {x:ev.pageX, y:ev.pageY};
    }
    return {
        x:ev.clientX + document.body.scrollLeft - document.body.clientLeft,
        y:ev.clientY + document.body.scrollTop  - document.body.clientTop
    };
}


function mouseMove(ev){
    ev         = ev || window.event;

    /*
    We are setting target to whatever item the mouse is currently on

    Firefox uses event.target here, MSIE uses event.srcElement
    */
    var target   = ev.target || ev.srcElement;
    var mousePos = mouseCoords(ev);

    // mouseOut event - fires if the item the mouse is on has changed
    if(lastTarget && (target!==lastTarget)){
        // reset the classname for the target element
        var origClass = lastTarget.getAttribute('origClass');
        if(origClass) lastTarget.className = origClass;
    }

    /*
    dragObj is the grouping our item is in (set from the createDragContainer function).
    if the item is not in a grouping we ignore it since it can't be dragged with this
    script.
    */
    var dragObj = target.getAttribute('DragObj');

     // if the mouse was moved over an element that is draggable
    if(dragObj!=null){

        // mouseOver event - Change the item's class if necessary
        if(target!=lastTarget){
            var oClass = target.getAttribute('overClass');
            if(oClass){
                target.setAttribute('origClass', target.className);
                target.className = oClass;
            }
        }

        // if the user is just starting to drag the element
        if(iMouseDown && !lMouseState){
            // mouseDown target
            curTarget     = target;

            // Record the mouse x and y offset for the element
            rootParent    = curTarget.parentNode;
            rootSibling   = curTarget.nextSibling;

            mouseOffset   = getMouseOffset(target, ev);

            // We remove anything that is in our dragHelper DIV so we can put a new item in it.
            for(var i=0; i<dragHelper.childNodes.length; i++) dragHelper.removeChild(dragHelper.childNodes[i]);

            // Make a copy of the current item and put it in our drag helper.
            dragHelper.appendChild(curTarget.cloneNode(true));
            dragHelper.style.display = 'block';

            // set the class on our helper DIV if necessary
            var dragClass = curTarget.getAttribute('dragClass');
            if(dragClass){
                dragHelper.firstChild.className = dragClass;
            }

            // disable dragging from our helper DIV (it's already being dragged)
            dragHelper.firstChild.removeAttribute('DragObj');

            /*
            Record the current position of all drag/drop targets related
            to the element.  We do this here so that we do not have to do
            it on the general mouse move event which fires when the mouse
            moves even 1 pixel.  If we don't do this here the script
            would run much slower.
            */
            var dragConts = DragDrops[dragObj];

            /*
            first record the width/height of our drag item.  Then hide it since
            it is going to (potentially) be moved out of its parent.
            */
            curTarget.setAttribute('startWidth',  parseInt(curTarget.offsetWidth));
            curTarget.setAttribute('startHeight', parseInt(curTarget.offsetHeight));
            curTarget.style.display  = 'none';

            // loop through each possible drop container
            for(var i=0; i<dragConts.length; i++){
                with(dragConts[i]){
                    var pos = getPosition(dragConts[i]);

                    /*
                    save the width, height and position of each container.

                    Even though we are saving the width and height of each
                    container back to the container this is much faster because
                    we are saving the number and do not have to run through
                    any calculations again.  Also, offsetHeight and offsetWidth
                    are both fairly slow.  You would never normally notice any
                    performance hit from these two functions but our code is
                    going to be running hundreds of times each second so every
                    little bit helps!

                    Note that the biggest performance gain here, by far, comes
                    from not having to run through the getPosition function
                    hundreds of times.
                    */
                    setAttribute('startWidth',  parseInt(offsetWidth));
                    setAttribute('startHeight', parseInt(offsetHeight));
                    setAttribute('startLeft',   pos.x);
                    setAttribute('startTop',    pos.y);
                }

                // loop through each child element of each container
                for(var j=0; j<dragConts[i].childNodes.length; j++){
                    with(dragConts[i].childNodes[j]){
                        if((nodeName=='#text') || (dragConts[i].childNodes[j]==curTarget)) continue;

                        var pos = getPosition(dragConts[i].childNodes[j]);

                        // save the width, height and position of each element
                        setAttribute('startWidth',  parseInt(offsetWidth));
                        setAttribute('startHeight', parseInt(offsetHeight));
                        setAttribute('startLeft',   pos.x);
                        setAttribute('startTop',    pos.y);
                    }
                }
            }
        }
    }

    // If we get in here we are dragging something
    if(curTarget){
        // move our helper div to wherever the mouse is (adjusted by mouseOffset)
        dragHelper.style.top  = mousePos.y - mouseOffset.y;
        dragHelper.style.left = mousePos.x - mouseOffset.x;

        var dragConts  = DragDrops[curTarget.getAttribute('DragObj')];
        var activeCont = null;

        var xPos = mousePos.x - mouseOffset.x + (parseInt(curTarget.getAttribute('startWidth')) /2);
        var yPos = mousePos.y - mouseOffset.y + (parseInt(curTarget.getAttribute('startHeight'))/2);

        // check each drop container to see if our target object is "inside" the container
        for(var i=0; i<dragConts.length; i++){
            with(dragConts[i]){
                if(((getAttribute('startLeft'))                               < xPos) &&
                    ((getAttribute('startTop'))                                < yPos) &&
                    ((getAttribute('startLeft') + getAttribute('startWidth'))  > xPos) &&
                    ((getAttribute('startTop')  + getAttribute('startHeight')) > yPos)){

                        /*
                        our target is inside of our container so save the container into
                        the activeCont variable and then exit the loop since we no longer
                        need to check the rest of the containers
                        */
                        activeCont = dragConts[i];

                        // exit the for loop
                        break;
                }
            }
        }

        // Our target object is in one of our containers.  Check to see where our div belongs
        if(activeCont){
            // beforeNode will hold the first node AFTER where our div belongs
            var beforeNode = null;

            // loop through each child node (skipping text nodes).
            for(var i=activeCont.childNodes.length-1; i>=0; i--){
                with(activeCont.childNodes[i]){
                    if(nodeName=='#text') continue;

                    // if the current item is "After" the item being dragged
                    if(
                        curTarget != activeCont.childNodes[i]                              &&
                        ((getAttribute('startLeft') + getAttribute('startWidth'))  > xPos) &&
                        ((getAttribute('startTop')  + getAttribute('startHeight')) > yPos)){
                            beforeNode = activeCont.childNodes[i];
                    }
                }
            }

            // the item being dragged belongs before another item
            if(beforeNode){
                if(beforeNode!=curTarget.nextSibling){
                    activeCont.insertBefore(curTarget, beforeNode);
                }

            // the item being dragged belongs at the end of the current container
            } else {
                if((curTarget.nextSibling) || (curTarget.parentNode!=activeCont)){
                    activeCont.appendChild(curTarget);
                }
            }

            // make our drag item visible
            if(curTarget.style.display!=''){
                curTarget.style.display  = '';
            }
        } else {

            // our drag item is not in a container, so hide it.
            if(curTarget.style.display!='none'){
                curTarget.style.display  = 'none';
            }
        }
    }

    // track the current mouse state so we can compare against it next time
    lMouseState = iMouseDown;

    // mouseMove target
    lastTarget  = target;

    // track the current mouse state so we can compare against it next time
    lMouseState = iMouseDown;

    // this helps prevent items on the page from being highlighted while dragging
    return false;
}

function mouseUp(ev){
    if(curTarget){
        // hide our helper object - it is no longer needed
        dragHelper.style.display = 'none';

        // if the drag item is invisible put it back where it was before moving it
        if(curTarget.style.display == 'none'){
            if(rootSibling){
                rootParent.insertBefore(curTarget, rootSibling);
            } else {
                rootParent.appendChild(curTarget);
            }
        }

        // make sure the drag item is visible
        curTarget.style.display = '';
    }
    curTarget  = null;
    iMouseDown = false;
}

function mouseDown(){
    iMouseDown = true;
    if(lastTarget){
        return false;
    }
}

document.onmousemove = mouseMove;
document.onmousedown = mouseDown;
document.onmouseup   = mouseUp;

window.onload = function(){
    // Create our helper object that will show the item while dragging
    dragHelper = document.createElement('DIV');
    dragHelper.style.cssText = 'position:absolute;display:none;';

    CreateDragContainer(
        document.getElementById('DragContainer1'),
        document.getElementById('DragContainer2'),
        document.getElementById('DragContainer3')
    );

    document.body.appendChild(dragHelper);
}
</script><!--the mouse over and dragging class are defined on each item-->

</head>
<body>

<br/>
<div class="DragContainer" id="DragContainer1">
    <div class="DragBox" id="Item1"  overClass="OverDragBox" dragClass="DragDragBox">Item #1</div>
    <div class="DragBox" id="Item2"  overClass="OverDragBox" dragClass="DragDragBox">Item #2</div>
    <div class="DragBox" id="Item3"  overClass="OverDragBox" dragClass="DragDragBox">Item #3</div>
    <div class="DragBox" id="Item4"  overClass="OverDragBox" dragClass="DragDragBox">Item #4</div>
</div>
<div class="DragContainer" id="DragContainer2">
    <div class="DragBox" id="Item5"  overClass="OverDragBox" dragClass="DragDragBox">Item #5</div>
    <div class="DragBox" id="Item6"  overClass="OverDragBox" dragClass="DragDragBox">Item #6</div>
    <div class="DragBox" id="Item7"  overClass="OverDragBox" dragClass="DragDragBox">Item #7</div>
    <div class="DragBox" id="Item8"  overClass="OverDragBox" dragClass="DragDragBox">Item #8</div>
</div>
<div class="DragContainer" id="DragContainer3">
    <div class="DragBox" id="Item9"  overClass="OverDragBox" dragClass="DragDragBox">Item #9</div>
    <div class="DragBox" id="Item10" overClass="OverDragBox" dragClass="DragDragBox">Item #10</div>
    <div class="DragBox" id="Item11" overClass="OverDragBox" dragClass="DragDragBox">Item #11</div>
    <div class="DragBox" id="Item12" overClass="OverDragBox" dragClass="DragDragBox">Item #12</div>
</div>
<br/>

</body>
</html>
");
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3
  • The article you referenced is exactly what asker needs. You should have started with "read this article", emphasizing that your code is just another example.
    – buti-oxa
    Commented Nov 1, 2008 at 18:34
  • Why this message has not been added in bottom of original question ? I don't understand. Is this message an answer ? In your question, you ask some explanation about how to drag and drop using Jabascript. I read your answer, but I don't see explanations, only comment in code.
    – schlebe
    Commented May 19, 2020 at 13:00
  • I have tried to put your code in Code Snipped but your drag and drop is not working. Can you please migrate your example in Code Snippet so that we can check your example on line ?
    – schlebe
    Commented May 19, 2020 at 13:16
3

Find 2x of:

dragHelper.style.top  = mousePos.y - mouseOffset.y;
dragHelper.style.left = mousePos.x - mouseOffset.x;

change to:

dragHelper.style.top  = mousePos.y - mouseOffset.y + 'px';
dragHelper.style.left = mousePos.x - mouseOffset.x + 'px';

Works on FF. 3.6

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1

the answer is here jQuery drag-and-drop DIV selection with images and text

<script type="text/javascript" src="http://www.dynamicdrive.com/dynamicindex11/domdrag/dom-drag.js"></script>
<script type="text/javascript">
Drag.init(document.getElementById("exampleid")); //sets the id to look for to make object draggable
</script>
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