<SCRIPT language=JavaScript>var now = new Date()
var hour=now.getHours();
document.write("<font color=#FFFF99 size=1>");
document.write("</font>");
if (hour>=0 && hour<12)
{ document.write("上午好!");}
else if (hour>=12 && hour<18)
{ document.write("下午好!");}
else
{ document.write("晚上好!");}
</SCRIPT>
var hour=now.getHours();
document.write("<font color=#FFFF99 size=1>");
document.write("</font>");
if (hour>=0 && hour<12)
{ document.write("上午好!");}
else if (hour>=12 && hour<18)
{ document.write("下午好!");}
else
{ document.write("晚上好!");}
</SCRIPT>
execute...
} else if(expressionb) {} else {}----------------------------------------------
<SCRIPT language=JavaScript>var now = new Date();
var hour=now.getHours();
document.write("<font color=#FFFF99 size=1>");
document.write("</font>");
if((hour>=0) && (hour<12)){
document.write("上午好!");
} else if ((hour>=12) && (hour<18)) {
document.write("下午好!");
} else {
document.write("晚上好!");
}
</SCRIPT>