function focusIf(c, f, m){
	return c && (m && alert(m), f.focus()), c;
}

function isEmpty(f){
	for(var i = -1, l = (a = arguments).length, r = /\S/, f; ++i < l;)
		if(focusIf(!(f = a[i]).readonly && !f.disabled && !r.test(f.value), f, "Preencha o campo " + f.name.toUpperCase()))
			return 1;
	return 0;
}