function HideMessageBox()
{
	document.getElementById("overlay").style.visibility = "hidden";
}
function ShowMessageBox()
{
	document.getElementById("overlay").style.visibility = "visible";
}
function ClearMessageBox()
{
	document.getElementById("messagebox_top").innerHTML ="";
		document.getElementById("messagebox_middle").innerHTML = "";
		document.getElementById("messagebox_bottom").innerHTML = "";
}
function MessageBox(Heading,Text,Buttons, Result)
{
	var BottomHTML = "";
		if(Buttons == "alert")
		{
			BottomHTML = "<button onclick='" + Result + "(\"ok\")'>Ok</button>";
		}
		if(Buttons == "confirm")
		{
			BottomHTML = "<button onclick='" + Result + "(\"ok\")'>Ok</button>" + "<button onclick='" + Result + "(\"cancel\")'>Cancel</button>";
		}
		if(Buttons == "yesno")
		{
			BottomHTML = "<button onclick='" + Result + "(\"yes\")'>Yes</button>" + "<button onclick='" + Result + "(\"no\")'>No</button>";
		}
		document.getElementById("messagebox_top").innerHTML =Heading;
		document.getElementById("messagebox_middle").innerHTML = Text;
		document.getElementById("messagebox_bottom").innerHTML = BottomHTML;
		
	this.Hide = HideMessageBox();

	this.Show = ShowMessageBox();
}