Sto usando il javascript "jquery.easydrag.js" per muovere degli oggetti all'interno del sito. Solo che vorrei limitarne il movimento all'interno di un certo div. Come posso fare?
codice:
/**
* EasyDrag 1.1 - Drag & Drop jQuery Plug-in
*
* For usage instructions please visit http://fromvega.com
*
* Copyright (c) 2007 fromvega
*/
(function($){
// to track if the mouse button is pressed
var isMouseDown = false;
// to track the current element being dragged
var currentElement = null;
// callback holders
var dropCallbacks = {};
var dragCallbacks = {};
// global position records
var lastMouseX;
var lastMouseY;
var lastElemTop;
var lastElemLeft;
// returns the mouse (cursor) current position
$.getMousePosition = function(e){
var posx = 0;
var posy = 0;
if (!e) var e = window.event;
if (e.pageX || e.pageY) {
posx = e.pageX;
posy = e.pageY;
}
else if (e.clientX || e.clientY) {
posx = e.clientX + document.body.scrollLeft + document.documentElement.scrollLeft;
posy = e.clientY + document.body.scrollTop + document.documentElement.scrollTop;
}
return { 'x': posx, 'y': posy };
}
// updates the position of the current element being dragged
$.updatePosition = function(e) {
var pos = $.getMousePosition(e);
var spanX = (pos.x - lastMouseX);
var spanY = (pos.y - lastMouseY);
$(currentElement).css("top", (lastElemTop + spanY));
$(currentElement).css("left", (lastElemLeft + spanX));
}
// when the mouse is moved while the mouse button is pressed
$(document).mousemove(function(e){
if(isMouseDown){
// update the position and call the registered function
$.updatePosition(e);
if(dragCallbacks[currentElement.id] != undefined){
dragCallbacks[currentElement.id](e);
}
return false;
}
});
// when the mouse button is released
$(document).mouseup(function(e){
if(isMouseDown){
isMouseDown = false;
if(dropCallbacks[currentElement.id] != undefined){
dropCallbacks[currentElement.id](e);
}
return false;
}
});
// register the function to be called while an element is being dragged
$.fn.ondrag = function(callback){
return this.each(function(){
dragCallbacks[this.id] = callback;
});
}
// register the function to be called when an element is dropped
$.fn.ondrop = function(callback){
return this.each(function(){
dropCallbacks[this.id] = callback;
});
}
// set an element as draggable
$.fn.easydrag = function(){
return this.each(function(){
// if no id is defined assign a unique one
if(undefined == this.id) this.id = 'easydrag'+time();
// change the mouse pointer
$(this).css("cursor", "move");
// when an element receives a mouse press
$(this).mousedown(function(e){
// set it as absolute positioned
$(this).css("position", "absolute");
// set z-index
$(this).css("z-index", "10000");
// update track variables
isMouseDown = true;
currentElement = this;
// retrieve positioning properties
var pos = $.getMousePosition(e);
lastMouseX = pos.x;
lastMouseY = pos.y;
lastElemTop = parseInt($(this).css("top"));
lastElemLeft = parseInt($(this).css("left"));
// IE doesn't return a valid value for 'top' and 'left' if they aren't explicit set
// so we use a quick work around and set a specific position to start with
if(isNaN(lastElemTop )) lastElemTop = lastMouseY - this.offsetHeight/2;
if(isNaN(lastElemLeft)) lastElemLeft = lastMouseX - this.offsetWidth/2;
$.updatePosition(e);
return false;
});
});
}
})(jQuery);