function time_of_day() {
var today=new Date(); 
var time=today.getHours();
time_statement=""
if(time>=4 && time<8)
time_statement="Bonjour,"
if(time>=8 && time<12)
time_statement="Bonne matinée,"
if(time>=12 && time<13)
time_statement="Bon appétit," 
if(time>=13 && time<17)
time_statement="Bon après-midi,"
if(time>=17 && time<22)
time_statement="Bonsoir,"
if(time>=22 || time<4)
time_statement="Bonne nuit,"
}
function bonjour(){
time_of_day();
document.write (time_statement);
}