			checked = checkbox.checked;
			}
			if(checked == true){
				total_size += size;
				total_page += page;
			}else{
				total_size -= size;
				total_page -= page;
			}

			var buttons_disabled = true;
			var file_too_big = true;
			if(total_size <= 15728640){
				file_too_big = false;
				if(total_size > 0){
					buttons_disabled = false;
				}
			}

			document.getElementById('view_button').disabled = buttons_disabled;
			document.getElementById('download_button').disabled = buttons_disabled;
			documen