var mouse_x = 0;
var mouse_y = 0;
var distance_to_right_edge = 0;
var distance_to_bottom = 0;
var contextmenu = null;

//addLoadEvent(onstart);

function onstart() {
	contextmenu = document.getElementById('thecontextmenu');
	addGenericEvent(document,'mousemove',mousemove);
	addGenericEvent(document,'click',hide_contextmenu);
}


function context_menuitem_highlight(element, color) {
	element.className = 'highlight';
}

function context_menuitem_unhighlight(element) {
	element.className = '';
}

function show_contextmenu(event) {

	get_page_boundaries();
	contextmenu.style.left = mouse_x+"px";
	contextmenu.style.top = mouse_y+"px";
	contextmenu.style.visibility = "visible";

	// adjust menu if near window edge
	if (distance_to_right_edge < contextmenu.offsetWidth)
		contextmenu.style.left = 2+mouse_x - contextmenu.offsetWidth+"px";  // The 2+ is not some dumb kludge -
	if (distance_to_bottom < contextmenu.offsetHeight)                    // it places the menu just under the pointer,
		contextmenu.style.top = 2+mouse_y - contextmenu.offsetHeight+"px";  // instead of just outside

	try {
		window.getSelection().collapseToStart();  // try to compensate for tendency to treat right-clicking as text selection
	} catch (e) {} // do nothing

	// prevent the event from bubbling up and causing the regular browser context menu to appear.
	event.cancelBubble = true;
	if (event.stopPropagation) event.stopPropagation();
	if (event.preventDefault) event.preventDefault();

	return false;
}

function hide_contextmenu() {
	contextmenu.style.visibility = "hidden";
}


function addLoadEvent(func) {
	if (window.addEventListener)
		window.addEventListener("load",func,false);
	else if (document.addEventListener)
		document.addEventListener("load",func,false);
	else if (window.attachEvent)
		window.attachEvent("onload",func);
	else if (document.attachEvent)
		document.attachEvent("onload",func);
}

function addGenericEvent(source, trigger, func) {
	if (source.addEventListener)
		source.addEventListener(trigger,func,false);
	else if (source.attachEvent)
		source.attachEvent("on"+trigger,func);
}

function window_x() {
	if (window.screenX)
		return window.screenX
	else if (window.screenLeft)
		return window.screenLeft;
}

function window_y() {
	if (window.screenY)
		return window.screenY
	else if (window.screenTop)
		return window.screenTop;
}

function mousemove(e) {
	if (e && e.clientX && typeof(window.scrollY) == 'number') { // Moz
		mouse_x = e.clientX + window.scrollX;
		mouse_y = e.clientY + window.scrollY;
		event_target = e.target;
	}
	else if (window.event) { // IE
		if (document.documentElement)   // Explorer 6 Strict
			{
			mouse_x = window.event.clientX + document.documentElement.scrollLeft - 4;
			mouse_y = window.event.clientY + document.documentElement.scrollTop - 4;
		}
		else if (document.body) // all other Explorers
			{
			mouse_x=window.event.clientX+document.body.scrollLeft-4;
			mouse_y=window.event.clientY+document.body.scrollTop-4;
		}

		mouse_window_x = window.event.clientX;
		mouse_window_y = window.event.clientY;
	}
}

function get_page_boundaries()
{
	if (window.innerWidth) {
		distance_to_right_edge = window.innerWidth-(mouse_x - window.scrollX)
		distance_to_bottom = window.innerHeight-(mouse_y - window.scrollY);

		//alert(window.innerHeight+' '+mouse_y);
	} else if (document.body.clientWidth) {
		distance_to_right_edge = document.body.clientWidth-mouse_x;
		distance_to_bottom = document.body.clientHeight-mouse_y;
	}
}