//*****************************************************************************
// Do not remove this notice.
//
// Copyright 2001 by Mike Hall.
// See http://www.brainjar.com for terms of use.
//*****************************************************************************

// Determine browser and version.

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;
	}

	// Treat any other "Gecko" browser as NS 6.1.

	s = "Gecko";
	if ((i = ua.indexOf(s)) >= 0) {
	    this.isNS = true;
	    this.version = 6.1;
	    return;
	}
}

var dragBrowser = new Browser();

// Global object to hold drag informatio.
var dragObj = new Object();
var dragObj_zIndex = 0;

function dragStart(event, id) {
	var el;
	var x, y;

	// If an element id was given, find it. Otherwise use the element being
	// clicked on.

	if (id) {
		dragObj.elNode = document.getElementById(id);
	}else {
		if (dragBrowser.isIE) {
				dragObj.elNode = window.event.srcElement;
		}
		if (dragBrowser.isNS) {
				dragObj.elNode = event.target;
		}

		// If this is a text node, use its parent element.

		if (dragObj.elNode.nodeType == 3) {
			dragObj.elNode = dragObj.elNode.parentNode;
		}
	}

	// Get cursor position with respect to the page.

	if (dragBrowser.isIE) {
		x = window.event.clientX + document.documentElement.scrollLeft + document.body.scrollLeft;
		y = window.event.clientY + document.documentElement.scrollTop + document.body.scrollTop;
	}
	if (dragBrowser.isNS) {
		x = event.clientX + window.scrollX;
		y = event.clientY + window.scrollY;
	}

	// Save starting positions of cursor and element.

	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;}

	// Update element's z-index.

	dragObj.elNode.style.zIndex = ++dragObj_zIndex;

	// Capture mousemove and mouseup events on the page.

	if (dragBrowser.isIE) {
		document.attachEvent("onmousemove", dragGo);
		document.attachEvent("onmouseup",   dragStop);
		window.event.cancelBubble = true;
		window.event.returnValue = false;
	}
	if (dragBrowser.isNS) {
		document.addEventListener("mousemove", dragGo,   true);
		document.addEventListener("mouseup",   dragStop, true);
		event.preventDefault();
	}
}

function dragGo(event) {

	var x, y;

	// Get cursor position with respect to the page.

	if (dragBrowser.isIE) {
		x = window.event.clientX + document.documentElement.scrollLeft + document.body.scrollLeft;
		y = window.event.clientY + document.documentElement.scrollTop + document.body.scrollTop;
	}
	if (dragBrowser.isNS) {
		x = event.clientX + window.scrollX;
		y = event.clientY + window.scrollY;
	}

	// Move drag element by the same amount the cursor has moved.

	dragObj.elNode.style.left = (dragObj.elStartLeft + x - dragObj.cursorStartX) + "px";
	dragObj.elNode.style.top  = (dragObj.elStartTop  + y - dragObj.cursorStartY) + "px";

	if (dragBrowser.isIE) {
		window.event.cancelBubble = true;
		window.event.returnValue = false;
	}
	if (dragBrowser.isNS) {
		event.preventDefault();
	}
}

function dragStop(event) {

	// Stop capturing mousemove and mouseup events.

	if (dragBrowser.isIE) {
		document.detachEvent("onmousemove", dragGo);
		document.detachEvent("onmouseup",   dragStop);
	}
	if (dragBrowser.isNS) {
		document.removeEventListener("mousemove", dragGo,   true);
		document.removeEventListener("mouseup",   dragStop, true);
	}
}

function getCursorPos(event){
	var curPos = new Object();

	// Get cursor position with respect to the page.

	if (dragBrowser.isIE) {
		curPos.x = window.event.clientX + document.documentElement.scrollLeft + document.body.scrollLeft;
		curPos.y = window.event.clientY + document.documentElement.scrollTop + document.body.scrollTop;
	}
	if (dragBrowser.isNS) {
		curPos.x = event.clientX + window.scrollX;
		curPos.y = event.clientY + window.scrollY;
	}

	return curPos;
}