function parsepagina () {
	
	if (document.getElementById('cup')) {
	  box = document.getElementById('content_home');				
		
		if (box.scrollHeight > box.offsetHeight) {
		  document.getElementById('cup').style.display = 'block';
		  document.getElementById('cdown').style.display = 'block';			
		}
	}
}

window.onload = parsepagina;

function scroll_down () {
  box = document.getElementById('content_home');
	
	box.scrollTop = box.scrollTop + 1;
}

function scroll_up () {
  box = document.getElementById('content_home');
	
	box.scrollTop = box.scrollTop - 1;
}

function set_scroll_down (type) {
  if (type) {
	 down_timer = setInterval('scroll_down()', 5); 
	} else {
	 clearInterval(down_timer);
	}
}

function set_scroll_up (type) {
  if (type) {
	 up_timer = setInterval('scroll_up()', 5); 
	} else {
	 clearInterval(up_timer);
	}
}