function info( string ){
	
	var info = document.getElementById( 'alert' );
	var novo = document.createElement( 'label' );
	var texto = document.createTextNode( string );
	novo.appendChild( texto );
	info.replaceChild( novo, info.getElementsByTagName( 'label' )[0] );
}


function validaForm(){
	
	var nome = document.getElementById( 'name' );
	
	if( nome.value == '' ){
		
		info( 'name field must be fill.' );
		nome.focus();
		return false;
	}
	
	if( nome.value.search( /^[a-zA-Z ]+$/ ) ){
	
		info( 'just type letters at name.' );
		nome.focus();
		return false;
	}
	
	var mail = document.getElementById( 'email' );

	if( mail.value == ''){
		
		info( 'e-mail field must be fill.' );
		mail.focus();
		return false;
	}
	
	if( mail.value.search( /^[\da-z]([\w-.]*[\w+])*@([\da-z][\w-]*[\da-z]\.)+[a-z]{2,9}$/) ){
		
		info( 'invalid e-mail.' );
		mail.focus();
		return false;
	}
	

	var message = document.getElementById( 'message' );
	
	if( message.value == ''){
		
		info( 'write a message, man!' );
		message.focus();
		return false;
	}

	info( 'message sucessfully sent.' );

}