function Browser() {
	var ua, s, i;
	this.isIE = false;
	this.isNS = false;
	this.version = null;
	ua = navigator.userAgent;
	s = "MSIE";
	if ( ( i = ua.indexOf( s ) ) >= 0 ) {
		this.isIE = true;
		this.version = parseFloat(ua.substr(i + s.length));
		return;
	}
	s = "Netscape6/";
	if ( ( i = ua.indexOf( s ) ) >= 0 ) {
		this.isNS = true;
		this.version = parseFloat(ua.substr(i + s.length));
		return;
	}
	s = "Gecko";
	if ( ( i = ua.indexOf( s ) ) >= 0 ) {
		this.isNS = true;
		this.version = 6.1;
		return;
	}
}
var browser = new Browser();
var dragObj = new Object();
dragObj.zIndex = 0;
function dragStart( event, id ) {
	var el, x, y;
	if ( id ) {
		dragObj.elNode = document.getElementById(id);
	} else {
		if ( browser.isIE ) {
			dragObj.elNode = window.event.srcElement;
		}
		if ( browser.isNS ) {
			dragObj.elNode = event.target;
		}
		if ( dragObj.elNode.nodeType == 3 ) {
			dragObj.elNode = dragObj.elNode.parentNode;
		}
	}
	if ( browser.isIE ) {
		x = window.event.clientX + document.documentElement.scrollLeft + document.body.scrollLeft;
		y = window.event.clientY + document.documentElement.scrollTop + document.body.scrollTop;
	}
	if ( browser.isNS ) {
		x = event.clientX + window.scrollX;
		y = event.clientY + window.scrollY;
	}
	dragObj.cursorStartX = x;
	dragObj.cursorStartY = y;
	dragObj.elStartLeft = parseInt( dragObj.elNode.style.left, 10 );
	dragObj.elStartTop = parseInt( dragObj.elNode.style.top, 10 );
	if ( isNaN( dragObj.elStartLeft ) ) {
		dragObj.elStartLeft = 0;
	}
	if ( isNaN( dragObj.elStartTop ) ) {
		dragObj.elStartTop  = 0;
	}
	dragObj.elNode.style.zIndex = ++dragObj.zIndex;
	if ( browser.isIE ) {
		document.attachEvent( "onmousemove", dragGo );
		document.attachEvent( "onmouseup", dragStop );
		window.event.cancelBubble = true;
		window.event.returnValue = false;
	}
	if ( browser.isNS ) {
		document.addEventListener( "mousemove", dragGo, true );
		document.addEventListener( "mouseup", dragStop, true );
		event.preventDefault();
	}
}
function dragGo( event ) {
	var x, y;
	if ( browser.isIE ) {
		x = window.event.clientX + document.documentElement.scrollLeft + document.body.scrollLeft;
		y = window.event.clientY + document.documentElement.scrollTop + document.body.scrollTop;
	}
	if ( browser.isNS ) {
		x = event.clientX + window.scrollX;
		y = event.clientY + window.scrollY;
	}
	dragObj.elNode.style.left = ( dragObj.elStartLeft + x - dragObj.cursorStartX ) + "px";
	dragObj.elNode.style.top = ( dragObj.elStartTop  + y - dragObj.cursorStartY ) + "px";
	if ( browser.isIE ) {
		window.event.cancelBubble = true;
		window.event.returnValue = false;
	}
	if ( browser.isNS ) {
		event.preventDefault();
	}
}
function dragStop( event ) {
	if ( browser.isIE ) {
		document.detachEvent( "onmousemove", dragGo );
		document.detachEvent( "onmouseup", dragStop );
	}
	if ( browser.isNS ) {
		document.removeEventListener( "mousemove", dragGo, true );
		document.removeEventListener( "mouseup", dragStop, true );
	}
}