function toggle(div_id) {
    var el = document.getElementById(div_id);
    if (el.style.display == 'none') { el.style.display = 'block'; }
    else { el.style.display = 'none'; }
}
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 
    {
    	//alert("clientHeight: "+document.body.parentNode.clientHeight);
    	//alert("scrollHeight: "+document.body.parentNode.scrollHeight);
        if (document.body.parentNode.clientHeight > document.body.parentNode.scrollHeight) 
        {
            blanket_height = document.body.parentNode.clientHeight;
            //document.getElementsByTagName('body')[0].clientHeight
        } 
        else 
        {
            blanket_height = document.body.parentNode.scrollHeight;
        }
        //alert("scrollHeight: "+document.body.parentNode.scrollHeight);
        //alert("clientHeight: "+document.documentElement.clientHeight);
    }
    var blanket = document.getElementById('blanket');
    var wraptop = document.getElementById('wraptop').offsetHeight;
   // alert("wraptop: "+wraptop);
    blanket.style.height = wraptop + 'px';
   // blanket.style.height = blanket_height + 'px';
    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) 
{
    var viewportwidth;
    var viewportheight
    var window_width;
    var window_height;
    
    if (typeof window.innerWidth != 'undefined') 
    {
        viewportwidth = window.innerWidth;
        viewportheight = window.innerHeight;
    } 
    else 
    {
        viewportwidth = document.documentElement.clientWidth;
        viewportheight = 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;
        }
    }
    
    if ((viewportheight > document.body.parentNode.scrollWidth) && (viewportheight > document.body.parentNode.clientWidth)) 
        {
            window_height = viewportheight;
        } 
        else 
        {
            if (document.body.parentNode.clientHeight > document.body.parentNode.scrollHeight) 
            {
                window_height = document.body.parentNode.clientHeight;
            }
            else 
            {
                window_height = document.body.parentNode.scrollHeight;
            }
    }
    
    var popUpDiv = document.getElementById(popUpDivVar);
    window_width = window_width / 2 - 285; //285 is half popup's width
    popUpDiv.style.left = window_width + 'px';
    
    
    /*window_height = window_height / 2 - 144; 
    //var arrayPageScroll = document.viewport.getScrollOffsets();
    //var popboxTop = arrayPageScroll[1] + 20;
    popUpDiv.style.top = window_height + 'px';*/
    
    popUpDiv.style.top = 100 + 'px';
    window.scrollTo(0, 0);
    
     /*var arrayPageScroll = document.viewport.getScrollOffsets();
     //alert("arrayPageScroll: "+arrayPageScroll[1]);
     var popboxTop = arrayPageScroll[1] + 20;
    popUpDiv.style.top = popboxTop + 'px';*/
     
}
function popup(windowname) {
    blanket_size(windowname);
    window_pos(windowname);
    toggle('blanket');
    toggle(windowname);
}