Script Drag And Drop Where User Chooses Which Objects Are Present?
Aug 24, 2011
There is a website based game I would like to build, but I am not sure that the main functionality would be possible to program. I have tried to do as much research as possible. I know that javascript can do drag and drop, but would it be possible for the user to specify which images (out of a catalogue of thousands) they would like to be present on screen/toplay with?
It would need to work like this: The user is presented with a catalgoue of images. They can refine this catalogue according to things like colour, type etc. The user chooses which images they would like to play with by adding them to their personal choices (e.g. with an 'add this item' button). In the next step the user is taken to a page showing all the items added to their personal list, which they can then drag and drop around the screen. The user can then save/share their 'creation'.
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Feb 20, 2011
So, what it does: You can successfully drag something anywhere, but when you click it again, it resets to its original position (I don't know why), and when you try to drag it again, as soon as your cursor touches the object it disappears (I don't know why). why it is happening and how to fix it!
// JavaScript Document
var posX;
var posY;
var element;
[Code]....
the html is a simple (position is set to relative):
<p id="square" onmousedown="drag(event)">meep</p>
EDIT: This is the first time I've written javascript code and would like to learn the basics, which is why I am not using a library.
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Jan 25, 2007
I am using YUI's Drag and Drop utility to add some drag & drop functionality to a CMS I'm building.
This works just fine and is very easy to set up, but the thing I'm wondering about, how do I restrict the dragging? In other words; how can I make sure an element gets dragged within the borders of, say, some div and not outside them?
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Jan 11, 2006
After a good deal of internal development, I've decided this library will do more good in the wild. It works in IE6, Safari 2, Opera 9, Firefox 1.5, and IE5.5/Mac (sort of buggy behavior with text selection in IE5.5/Mac though). It should also work in virtually any version of Gecko, Opera 6+, Safari 1, and IE5+ (anybody who wants to test those, feel free). The scripting is highly efficient, and only exposes two functions globally, Draggable and Droppable. The below code is licensed under the LGPL, though it is available under other licenses per request.
Let me know if you have any issues with it - this is something I'm interested in maintaining. Also, compared to other scripts, such as script.tac.ulo.us, this is much less code (lots of whitespace/comments could be taken out), and more widely supported across browsers.
Other than below, it can be found here: http://www.jasonkarldavis.com/scripts/dragdropable/dragdropable.html
// dragdropable.js (1.0.1)
//Copyright (C) 2006 Jason Davis, www.jasonkarldavis.com
//This code is licensed under the LGPL:
//http://www.gnu.org/licenses/lgpl.html
//
// Documentation:
//This script exposes two global variables, Draggable and Droppable. To make an
//element draggable, simply call `Draggable(element)`. This sets the necessary
//CSS properties and event handlers. It also overrides the addEventListener and
//and attachEvent methods (if present) to include the following events:
//onstart(When the element begins dragging)
//ondrag(When the element is being dragged)
//onstop(When the element has stopped dragging)
//You may also assign element.onstart, element.ondrag, and element.onstart to
//add event listeners.
//Lastly, if you need to physically prevent an element from dragging, you may
//call event.preventDefault() from within the onstart handler.
//
//To make an element droppable (have things dragged onto it), call
//`Droppable(element)`. This sets the necessary event handlers and coordinate
//searches. Once again, it overrides addEventListener and attachEvent to
//include the following events:
//onhover(When another element has been dragged over the element)
//ondrop(When another element has been dropped onto the element)
//onunhover(When another element has been dragged off the element)
//As before, you may also set element.onhover, element.ondrop, and
//element.onunhover directly.
//To remove all drop points from the current session, call `Droppable.reset()`.
//
//The event object is also extended with the following properties:
//dragTarget(The element being dragged)
//dropTarget(The element being dropped onto)
//
// Known bugs:
//* removeEventListener and detachEvent do not work with the custom events.
//Workaround: Use direct assignment (element.onevent) instead.
//* There is no way to remove a single drop point.
//Workaround: Call Droppable.reset(), then reinitialize the other drop points.
//* There is no way to remove dragging from an element.
//Workaround: element.onstart = function(event) { event.preventDefault() }
//* Changing position of droppable elements after initialization breaks drop
//Workaround: Static droppables are much faster than moving ones. Either call
//Droppable.reset() and reinitialize often, or ask the author to modify the
//script to account for this (and accept the resulting slowdown)
function Draggable(element) {
// initialize drag variable
var x = 0, y = 0, oldMouseMove, oldMouseUp;
// get style properties of element
var computedStyle;
if (typeof document.defaultView != "undefined" && typeof document.defaultView.getComputedStyle != "undefined")
computedStyle = document.defaultView.getComputedStyle(element, "");
else if (typeof element.currentStyle != "undefined")
computedStyle = element.currentStyle;
else
computedStyle = element.style;
// prep element for dragging
if (computedStyle.position == "static" || computedStyle.position == "")
element.style.position = "relative";
if (computedStyle.zIndex == "auto" || computedStyle.zIndex == "")
element.style.zIndex = 1;
element.style.left = isNaN(parseInt(computedStyle.left)) ? "0" : computedStyle.left;
element.style.top = isNaN(parseInt(computedStyle.top )) ? "0" : computedStyle.top;
// default event listeners
function onstart(event) {
event.dragTarget = element;
x = event.clientX;
y = event.clientY;
// Override preventDefault
event.preventDefault = (function(original) {
return function() {
element.ownerDocument.onmousemove = oldMouseMove;
element.ownerDocument.onmouseup = oldMouseUp;
original.call(event);
}
})(event.preventDefault || function() {});
if (element.onstart) element.onstart(event);
}
function ondrag(event) {
event.dragTarget = element;
element.style.left = parseInt(element.style.left) + event.clientX - x + "px";
element.style.top = parseInt(element.style.top) + event.clientY - y + "px";
x = event.clientX;
y = event.clientY;
Droppable.query(event);
if (element.ondrag) element.ondrag(event);
}
function onstop(event) {
event.dragTarget = element;
Droppable.query(event);
if (element.onstop) element.onstop(event);
}
// make listeners active
element.onmousedown = (function(oldMouseDown) {
return function() {
// Call old listener
if (oldMouseDown) oldMouseDown.apply(this, arguments);
// Store old event handlers
oldMouseMove = this.ownerDocument.onmousemove;
oldMouseUp = this.ownerDocument.onmouseup;
// Setup events
this.ownerDocument.onmousemove = function() {
// Call old listener
if (oldMouseMove) oldMouseMove.apply(this, arguments);
// Call ondrag
ondrag.call(element, arguments[0] || event);
return false;
}
this.ownerDocument.onmouseup = function() {
// Call old listener
if (oldMouseUp) oldMouseUp.apply(this, arguments);
// Call onstop
onstop.call(element, arguments[0] || event);
// Restore old event listeners
this.onmousemove = oldMouseMove;
this.onmouseup = oldMouseUp;
return false;
}
// Call onstart
onstart.call(this, arguments[0] || event);
return false;
}
})(element.onmousedown);
// override event attachers
if (element.addEventListener)
element.addEventListener = (function(original) {
return function(event, listener, useCapture) {
switch (event) {
case "start":
onstart = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(onstart);
break;
case "drag":
ondrag = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(ondrag);
break;
case "stop":
onstop = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(onstop);
break;
default:
original.call(element, event, listener, useCapture);
}
}
})(element.addEventListener);
if (element.attachEvent)
element.attachEvent = (function(original) {
return function(event, listener) {
switch (event) {
case "onstart":
onstart = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(onstart);
break;
case "ondrag":
ondrag = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(ondrag);
break;
case "onstop":
onstop = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(onstop);
break;
default:
original.call(element, event, listener);
}
}
})(element.attachEvent);
if (window.attachEvent)
window.attachEvent("onbeforeunload", function() {
onstart = ondrag = onstop = element.onmousedown = element.addEventListener = element.attachEvent = null;
element = null;
});
}
// initialize Droppable in the global scope
var Droppable;
(function() {
if (document.getBoxObjectFor) {
function getOffset(element) {
var box = document.getBoxObjectFor(element);
return { x: box.x, y: box.y };
}
}
else if (document.all && navigator.appName == "Microsoft Internet Explorer" && !window.opera) {
function getOffset(element) {
var range = document.body.createTextRange();
range.moveToElementText(element);
var rect = range.getBoundingClientRect();
return { x: rect.left, y: rect.top };
}
}
else {
function getOffset(element) {
var accumulator = arguments[1] || { x: 0, y: 0 };
if (element && element != document.body) {
accumulator.x += element.offsetLeft;
accumulator.y += element.offsetTop;
return getOffset(element.offsetParent, accumulator);
}
else {
return accumulator;
}
}
}
// initialize private pointers to current target information
var cTarget = null, cHover = null, cUnhover = null, cDrop = null;
function hotSpots(x,y) {
cTarget = cHover = cUnhover = cDrop = null;
}
// declare Droppable within the private scope
Droppable = function(element) {
// Calculate offset
var offset = getOffset(element);
// Calculate other edge offset
var edge = { x: offset.x + element.offsetWidth, y: offset.y + element.offsetHeight };
// Assign a finder function
hotSpots = (function(old) {
return function(x,y) {
if (offset.x <= x && x <= edge.x && offset.y <= y && y <= edge.y) {
cTarget = element;
cHover = onhover;
cUnhover = onunhover;
cDrop = ondrop;
}
else {
old(x,y);
}
}
})(hotSpots);
// default event listeners
function onhover(event) {
event.dropTarget = element;
if (element.onhover) element.onhover(event);
}
function onunhover(event) {
event.dropTarget = element;
if (element.onunhover) element.onunhover(event);
}
function ondrop(event) {
event.dropTarget = element;
if (element.ondrop) element.ondrop(event);
}
// override event attachers
if (element.addEventListener)
element.addEventListener = (function(original) {
return function(event, listener, useCapture) {
switch (event) {
case "hover":
onhover = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(onhover);
break;
case "unhover":
onunhover = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(onunhover);
break;
case "drop":
ondrop = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(ondrop);
break;
default:
original.call(element, event, listener, useCapture);
}
}
})(element.addEventListener);
if (element.attachEvent)
element.attachEvent = (function(original) {
return function(event, listener) {
switch (event) {
case "onhover":
onhover = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(onhover);
break;
case "onunhover":
onunhover = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(onunhover);
break;
case "ondrop":
ondrop = (function(old) {
return function(event) { old.call(element,event); listener.call(element,event); }
})(ondrop);
break;
default:
original.call(element, event, listener);
}
}
})(element.attachEvent);
if (window.attachEvent)
window.attachEvent("onbeforeunload", function() {
hotSpots = onhover = onunhover = ondrop = element.addEventListener = element.attachEvent = cTarget = cHover = cUnhover = cDrop = null;
element = null;
});
}
// Setup a query method
Droppable.query = function(event) {
var oTarget = cTarget,
oHover = cHover,
oUnhover = cUnhover,
oDrop = cDrop;
var scrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft,
scrollTop = document.documentElement.scrollTop || document.body.scrollTop;
hotSpots(event.clientX + scrollLeft, event.clientY + scrollTop);
switch (event.type) {
case "mousemove": // onhover & onunhover
if (oTarget != null && oTarget != cTarget)
oUnhover.call(oTarget, event);
if (oTarget == null && cTarget != null)
cHover.call(cTarget, event);
break;
case "mouseup": // ondrop
if (cTarget != null) {
cUnhover.call(cTarget, event);
cDrop.call(cTarget, event);
}
break;
}
}
Droppable.reset = function() {
hotSpots = function(x,y) {
cTarget = cHover = cUnhover = cDrop = null;
}
hotSpots();
}
})();
// Fix the function prototype for IE5/Mac
if (typeof Function.prototype.apply == "undefined")
Function.prototype.apply = function(scope, args) {
if (!args) args = [];
var index = 0, result;
do { -- index } while (typeof scope[index] != "undefined");
scope[index] = this;
switch (args.length) {
case 0:
result = scope[index]();
break;
case 1:
result = scope[index](args[0]);
break;
case 2:
result = scope[index](args[0], args[1]);
break;
case 3:
result = scope[index](args[0], args[1], args[2]);
break;
case 4:
result = scope[index](args[0], args[1], args[2], args[3]);
break;
default:
result = scope[index](args[0], args[1], args[2], args[3], args[4]);
break;
}
delete scope[index];
return result;
}
if (typeof Function.prototype.call == "undefined")
Function.prototype.call = function(scope) {
var args = new Array(Math.max(arguments.length-1, 0));
for (var i = 1; i < arguments.length; i++)
args[i-1] = arguments[i];
return this.apply(scope, args);
}
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Aug 12, 2009
I am using jQuery Tabs to make an ajax call for each tab when clicked. The ajax that displays is like inettuts. 3 or 4 columns of widgets that can be dragged and dropped. The problem that I am having, when I put the html of the result directly in the main page, it works as designed. When I click on a tab, it displays the page, but all the jquery functions in that ajax page are gone and I cannot sort, drag and drop anything. I suspect that the ajax page is not reading the javascripts in the head, which are on main page. Unfortunately I can't remove them to include them in ajax pages dynamically because I am also using them for other functions in main page. Is there a way to make those ajax pages read the javascripts on that main page?
[URL]
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