var CSS_DISPLAY_NONE = "none";
var CSS_DISPLAY_BLOCK = "block";
		
		
function aboutShow()
{
	var msg = "about";	
	//document.getElementById("about").innerHTML=msg;	
	popup('about');	
}

function aboutHide()
{
    popdown('about');    
}


function hideDisplay(id) {
    //document.getElementById(id).style.display = 'none';
	var name = "#"+id;    
	 $(name).fadeOut(200);
}
function showDisplay(id) {
	//document.getElementById(id).style.display = 'block';
	var name = "#"+id;    
	 $(name).fadeIn(200);
}
function showVisibility(id) {
    document.getElementById(id).style.visibility = 'visible';
}
function hideVisibility(id) {
    document.getElementById(id).style.visibility = 'hidden';
}


function blanket_size(popUpDivVar) {
    if (typeof window.innerWidth != 'undefined') {
        viewportheight = window.innerHeight;
    } else {
        viewportheight = document.documentElement.clientHeight;
    }
    if ((viewportheight > document.body.parentNode.scrollHeight) && (viewportheight > document.body.parentNode.clientHeight)) {
        blanket_height = viewportheight;
    } else {
        if (document.body.parentNode.clientHeight > document.body.parentNode.scrollHeight) {
            blanket_height = document.body.parentNode.clientHeight;
        } else {
            blanket_height = document.body.parentNode.scrollHeight;
        }
    }
    var blanket = document.getElementById('blanket');
    blanket.style.height = blanket_height + 'px';

    // heigth center about div
    //var popUpDiv = document.getElementById(popUpDivVar);
    //popUpDiv_height = blanket_height / 2 - 150; //150 is half popup's height
    //popUpDiv.style.top = popUpDiv_height + 'px';
}
function window_pos(popUpDivVar) {
    if (typeof window.innerWidth != 'undefined') {
        viewportwidth = window.innerHeight;
    } else {
        viewportwidth = document.documentElement.clientHeight;
    }
    if ((viewportwidth > document.body.parentNode.scrollWidth) && (viewportwidth > document.body.parentNode.clientWidth)) {
        window_width = viewportwidth;
    } else {
        if (document.body.parentNode.clientWidth > document.body.parentNode.scrollWidth) {
            window_width = document.body.parentNode.clientWidth;
        } else {
            window_width = document.body.parentNode.scrollWidth;
        }
    }

    // width center about div
    var popUpDiv = document.getElementById(popUpDivVar);
    window_width = window_width / 2 - 150; //150 is half popup's width
    popUpDiv.style.left = window_width + 'px';
}
function popup(windowname) {
    blanket_size(windowname);
    window_pos(windowname);
    showDisplay('blanket');  
    showDisplay(windowname);         
}
function popdown(windowname) {
    hideDisplay('blanket');
    hideDisplay(windowname);
}