/*******************
 dragable.js  v0.4
 http://www.obliquemotion.com/js/dragable.js
 license: http://creativecommons.org/licenses/by/1.0/
 by Byron Tredwell (byron(AT)obliquemotion(DOT)com)
******************/

function dragable(event,elm,boundingBox,movefunc,releaseFunc){

if(elm==null){
  if(event.srcElement){
    elm=event.srcElement;
  }else{
    elm=event.target;
  }
}

var maxLeft = 0;
var maxTop = 0;
var maxRight = 0;
var maxBottom = 0;

if (document.documentElement) {
   var maxRight = document.documentElement.offsetWidth;
   var maxBottom = document.documentElement.offsetHeight;
}else if (document.body && document.body.offsetWidth) {
   var maxRight = document.body.offsetWidth;
   var maxBottom = document.body.offsetHeight;
}

if(boundingBox != null && boundingBox != document.body)
{
  maxRight = boundingBox.offsetWidth;
  maxBottom = boundingBox.offsetHeight;
}

var x = parseInt(elm.style.left);
var y = parseInt(elm.style.top);

if(isNaN(x) == true)
   x = 0;
if(isNaN(y) == true)
   y = 0;
   
var deltaX = event.clientX - x;
var deltaY = event.clientY - y; 

stopBubbleStopReturn(event);
addListener(document,"mousemove",startDrag);
addListener(document,"mouseup",stopDrag);

  function startDrag(e){
     if(!e)
      var e = window.event;
    stopBubbleStopReturn(e);
    var newX = (e.clientX - deltaX);
    var newY = (e.clientY - deltaY);


    if( (newX >= 0 && newX <= maxRight-elm.offsetWidth) ){
      elm.style.left = newX + "px"; 
    }else if (newX < 0){
		elm.style.left  = "0px";
 	 } else {
		elm.style.left = maxRight-elm.offsetWidth + "px";
	 }
    
    if( (newY >= 0 && newY <= maxBottom-elm.offsetHeight)  ) {
      elm.style.top  = newY + "px";
 	 } else if (newY < 0){
		elm.style.top  = "0px";
 	 } else {
		 elm.style.top = maxBottom-elm.offsetHeight + "px";
	 }

    if(movefunc)
      movefunc(newX,newY)
  }
  
  function stopDrag(e){
     if(!e)
      var e = window.event;
    stopBubbleStopReturn(e);
    removeListener(document,"mousemove",startDrag);
    removeListener(document,"mouseup",stopDrag);
    if(releaseFunc)
      releaseFunc();
  }
}