function DisplayAlert(id,left,top) {
	
	
	var width = (self.innerWidth || (document.documentElement.clientWidth || document.body.clientWidth))/2 + (window.pageXOffset || document.documentElement.scrollLeft);
	var height = (self.innerHeight || (document.documentElement.clientHeight || document.body.clientHeight))/2 + (window.pageYOffset || document.documentElement.scrollTop);
	
	left = width/4-220;
	top = height-140;
	
    document.getElementById(id).style.left=left+'px';
    document.getElementById(id).style.top=top+'px';
    document.getElementById(id).style.display='block';
}

function validate_loggedin(ingelogd) 
{
   if (ingelogd == true)
   { 
      return true
   }
   else
   {
      DisplayAlert('AlertBox',100,450);
      return false
   }
}