function getHour(){
var currentTime = new Date();
return (currentTime.getHours());
}

function doGreeting(){
var hour=getHour();
var greeting="";

if (hour>0 && hour<12) greeting="Bom Dia!";
else if(hour>=12 && hour<18) greeting="Boa Tarde!";
else greeting="Boa Noite!";

return (greeting);
}