SOURCE

var time=new Date().getHours();
if(time<10){
  document.write('good morning');
}else if(time>=10 && time<=14){
  document.write('good day');
}else{
  document.write('good afternoon ');
}
var day=new Date().getDay();
switch(day){
  case 1:document.write('good monday');
    break;
  case 2:document.write('good Tuesday');
    break;
  case 3:document.write('good Thursday');
    break;
  case 1:document.write('good Tuesday');
    break;
  case 1:document.write('good Friday');
    break;
  case 1:document.write('good Saturday');
    break;
  case 1:document.write('good Sunday');
    break;
}