/*function overlay_login () {
  var pageSize = getPageSize();
  // set height of Overlay to take up whole page and show
  if ($('overlay_login')) {
    if ($('overlay_login').style.display == 'none') {
      $('overlay_login').style.height = (pageSize.pageHeight + 'px');
      $('overlay_login').style.width = (pageSize.pageWidth + 'px');
      $('overlay_login').style.display = 'block';
    } else {
      $('overlay_login').style.display = 'none';
    }
  }
}*/

function overlay_toggle_show () {
  var pageSize = getPageSize();
  // set height of Overlay to take up whole page and show
  
  if ($('overlay')) {
    $('overlay').onclick = function() { return false; }
    if ($('overlay').style.display == 'none') 
    {
    	var arrayPageSize = getPageSize();
    	Element.setHeight('overlay', arrayPageSize[1]);
    	new Effect.Appear('overlay', { duration: 0.2, from: 0.0, to: 0.8 });
    } else {
      new Effect.Fade('overlay', { duration: 0.2}); 
    }
  }
}


function center_div(div_id) {
  if ($(div_id)) { /// IE hacks
    divWidth  = Element.getDimensions($(div_id)).width;
    divHeight = Element.getDimensions($(div_id)).height;

    var windowScroll = getWindowScroll();

    var top = (windowScroll.height - divHeight)/2 + windowScroll.top;
    $(div_id).style.top = top + 'px';

    var left = (windowScroll.width - divWidth)/2;
    $(div_id).style.left = left + 'px';
  }
}

// getPageSize()
// Returns array with page width, height and window width, height
// Core code from - quirksmode.org
// Edit for Firefox by pHaez
//
function getPageSize(){
	
	var xScroll, yScroll;
	
	if (window.innerHeight && window.scrollMaxY) {	
		xScroll = document.body.scrollWidth;
		yScroll = window.innerHeight + window.scrollMaxY;
	} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
		xScroll = document.body.scrollWidth;
		yScroll = document.body.scrollHeight;
	} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
		xScroll = document.body.offsetWidth;
		yScroll = document.body.offsetHeight;
	}
	
	var windowWidth, windowHeight;
	if (self.innerHeight) {	// all except Explorer
		windowWidth = self.innerWidth;
		windowHeight = self.innerHeight;
	} else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
		windowWidth = document.documentElement.clientWidth;
		windowHeight = document.documentElement.clientHeight;
	} else if (document.body) { // other Explorers
		windowWidth = document.body.clientWidth;
		windowHeight = document.body.clientHeight;
	}	
	
	// for small pages with total height less then height of the viewport
	if(yScroll < windowHeight){
		pageHeight = windowHeight;
	} else { 
		pageHeight = yScroll;
	}

	// for small pages with total width less then width of the viewport
	if(xScroll < windowWidth){	
		pageWidth = windowWidth;
	} else {
		pageWidth = xScroll;
	}


	arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
	return arrayPageSize;
}

function getWindowScroll() {
  var w = window;
    var T, L, W, H;
    with (w.document) {
      if (w.document.documentElement && documentElement.scrollTop) {
        T = documentElement.scrollTop;
        L = documentElement.scrollLeft;
      } else if (w.document.body) {
        T = body.scrollTop;
        L = body.scrollLeft;
      }
      if (w.innerWidth) {
        W = w.innerWidth;
        H = w.innerHeight;
      } else if (w.document.documentElement && documentElement.clientWidth) {
        W = documentElement.clientWidth;
        H = documentElement.clientHeight;
      } else {
        W = body.offsetWidth;
        H = body.offsetHeight
      }
    }
    //alert ('top: '+ T+', left: '+ L+', width: '+ W+', height: '+H );
    return { top: T, left: L, width: W, height: H };
}