function abre_janela(nome, url, left, top, width, height, toolbar, menubar, statusbar, scrollbar, resizable)
{
	LeftPosition = (screen.width) ? (screen.width-width)/2: 0;
	TopPosition = (screen.height) ? (screen.height-height)/4: 0;
	toolbar_str = toolbar ? 'yes' : 'no';
	menubar_str = menubar ? 'yes' : 'no';
	statusbar_str = statusbar ? 'yes' : 'no';
	scrollbar_str = scrollbar ? 'yes' : 'no';
	resizable_str = resizable ? 'yes' : 'no';
	window.open(url,nome,'left='+LeftPosition+',top='+TopPosition+',width='+width+',height='+height+',toolbar='+toolbar_str+',menubar='+menubar_str+',status='+statusbar_str+',scrollbars='+scrollbar_str+',resizable='+resizable_str);
}

function show( id ){
	document.getElementById(id).style.display = 'block';
}

function hide( id ){
	document.getElementById(id).style.display = 'none';
}