function $(id){
	return document.getElementById(id);
}
function trim(str){
	return str.replace(/^\s+|\s+$/g,"");
}
function valida_formulario() {
	var css_input = "input", css_input_alert = "input_alert"; css_alert_msg = "alert_msg";
	/* valida nome */
	if (trim($('frmnome').value) == "") {
		$('frmnome').className = css_input_alert;
		$('frmnome').focus();
		$('alert_msg_frmnome').className = css_alert_msg;
		$('alert_msg_frmnome').innerHTML = "Informe seu nome.";
		return false;
	}else{
		$('frmnome').className = css_input;
		$('alert_msg_frmnome').className = "";
		$('alert_msg_frmnome').innerHTML = "";
	}
	/* valida e-mail */	
	var email_value = trim($('frmemail').value);
	if (email_value == "") {
		$('frmemail').className = css_input_alert;
		$('frmemail').focus();
		$('alert_msg_frmemail').className = css_alert_msg;
		$('alert_msg_frmemail').innerHTML = "Informe seu e-mail.";
		return false;
	}else if (email_value.indexOf("@") == -1 || email_value.indexOf(".") == -1) {
		$('frmemail').className = css_input_alert;
		$('frmemail').focus();
		$('alert_msg_frmemail').className = css_alert_msg;
		$('alert_msg_frmemail').innerHTML = "Informe seu e-mail corretamente.";
		return false;
	}else {
		$('frmemail').className = css_input;
		$('alert_msg_frmemail').className = "";
		$('alert_msg_frmemail').innerHTML = "";
	}
	/* valida comentarios */
	if (trim($('frmcomentarios').value) == "") {
		$('frmcomentarios').className = css_input_alert;
		$('frmcomentarios').focus();
		$('alert_msg_frmcomentarios').className = css_alert_msg;
		$('alert_msg_frmcomentarios').innerHTML = "Faça algum comentário.";
		return false;
	}else{
		$('frmcomentarios').className = css_input;
		$('alert_msg_frmcomentarios').className = "";
		$('alert_msg_frmcomentarios').innerHTML = "";
	}
}