codigo de un calendario en html

veronica
04 de Enero del 2005
queremos un ejemplo con el codigo de un calendario diseñado en html el mismo que al seleccionar por medio de un combo el mes y el año se despliege en forma de un calendario. O corregir el codigo del siguiente calendario y a la vez traducir linea por linea del codigo lo que realiza cada una.
gracias

<HTML>
<HEAD>
<TITLE></TITLE>
</HEAD>
<BODY> <SCRIPT LANGUAGE="JavaScript">
<!--
now = new Date();
nowDay = now.getDay();
nowDate = now.getDate();
nowMonth = now.getMonth() + 1;
nowYear = new String(now.getYear());
nowyearLen = nowYear.length
nowYear = nowYear.split("")
nowYear = nowYear[nowyearLen - 2] + nowYear[nowyearLen - 1]
j = 31;
startDate = 1;
tmpDate = nowDate;
tmpDay = nowDay;
start = false;
end = false;
monthName = new Array();
monthName[1] = "January";
monthName[2] = "February";
monthName[3] = "March";
monthName[4] = "April";
monthName[5] = "May";
monthName[6] = "June";
monthName[7] = "July";
monthName[8] = "August";
monthName[9] = "September";
monthName[10] = "October";
monthName[11] = "November";
monthName[12] = "December";
monthLen = new Array();
monthLen[1] = "31";
monthLen[2] = "28";
monthLen[3] = "31";
monthLen[4] = "30";
monthLen[5] = "31";
monthLen[6] = "30";
monthLen[7] = "31";
monthLen[8] = "31";
monthLen[9] = "30";
monthLen[10] = "31";
monthLen[11] = "30";
monthLen[12] = "31";
for (i = 0; i < j; i++){
tmpDate--;
tmpDay--;
if (tmpDay < 0){
tmpDay = 6;
}
if (tmpDate == 1){
i = 31;
}
}
document.write("<table border=2 bgcolor='white'><tr><td><table><tr>")
document.write("<td WIDTH=211 ALIGN=CENTER>" + monthName[nowMonth] + ' ' + nowYear + "</td>")
document.write("</tr></table><table border=2><tr>")
document.write("<td WIDTH=25 ALIGN=CENTER>SU</td><td WIDTH=25 ALIGN=CENTER>M</td><td WIDTH=25 ALIGN=CENTER>T</td><td WIDTH=25 ALIGN=CENTER>W</td><td WIDTH=25 ALIGN=CENTER>TH</td><td WIDTH=25 ALIGN=CENTER>F</td><td WIDTH=25 ALIGN=CENTER>SA</td></tr><tr>")
for (i = 0; i < 7; i++){
for (week = 0; week <= 6; week++){
if (startDate == nowDate){
document.write("<td WIDTH=25 ALIGN=CENTER bgcolor='yellow'><B><I>")
}
else{
document.write("<td WIDTH=25 ALIGN=CENTER bgcolor='white'>")
}

if (week == tmpDay){
start = true
}
if ((start == true)&&(end == false)){
document.write(startDate)
startDate++
}
if (startDate == nowDate){
document.write("</B></I>")
}
document.write("</td>")
if (startDate > monthLen[nowMonth]){

end = true
}
}
document.write("</tr>")
}
document.write("</tr></table></td></tr></table>")
// -->
</SCRIPT> </BODY>
</HTML>