date manipulation in javascript

The easiest is to not let the user make mistakes:
<FORM>
<SELECT NAME="theYear">
<OPTION VALUE="">Select a year
<OPTION VALUE="2000">2000
<OPTION VALUE="2001">2001
<OPTION VALUE="2002">2002
<OPTION VALUE="2003">2003
</SELECT>
<SELECT NAME="theMonth">
<OPTION VALUE="">Select a month
<OPTION VALUE="0">1
<OPTION VALUE="1">2
<OPTION VALUE="2">3
<OPTION VALUE="3">4
..
..
<OPTION VALUE="11">12
</SELECT>
<SELECT NAME="theDay">
<OPTION VALUE="">Select a day
<OPTION VALUE="1">1
<OPTION VALUE="2">2
<OPTION VALUE="3">3
<OPTION VALUE="4">4
..
..
<OPTION VALUE="31">31
</SELECT>
<input type="button" onClick="compare(this.form)" VALUE="compare">
and then use

<script>
/* Compare and calculate (c) 2000 Michel Plungjan */
function compare(theForm)
   theYear = theForm.theYear.options[theForm.theYear.selectedIndex].value;
   theMonth = theForm.theMonth.options[theForm.theMonth.selectedIndex].value;
   theDay = theForm.theMonth.options[theForm.theMonth.selectedIndex].value;

   userDate = new Date(theYear,theMonth,theDay);

   testYear = userDate.getYear();
   if (testYear<1000)testYear +=1900;
   if (testYear != theYear ||
userDate.getMonth() != theMonth ||
userDate.getDay() != theDay) {
   alert('Date is not correct');
   return false;

   now = new Date();
   if (userDate.getTime() < now.getTime()) alert('Date must be later than today');
}
</script>

I apologise for any typo.

Michel

PS: You might want to change to this:

function compare(theForm)
                                     theYear = theForm.theYear.options[theForm.theYear.selectedIndex].value;
                                     theMonth = theForm.theMonth.options[theForm.theMonth.selectedIndex].value;

                                     theDay = theForm.theMonth.options[theForm.theMonth.selectedIndex].value;
   if (theYear = '' || theMonth = '' ||theDay = '') {
   alert('Please select year and month and day');
   return false;
   }


and have a return true at the end of the function:

   return true;
}
</script>

Thank you.

I am using  perl program to genarate the HTML with the embeded javascript. There I have to create multiple same data entry form. That each form on same the page should have three date entry field execpt others. So I can not use the option control. May be it takes more space on the page and loading time. so I leave it for text box.
Any way thanks for your coding. I will get some knowladge from you script. Keeping that I will mannage.

Thank you one again.

Xabi, are you poaching???

Michel

Sorry michael, as you know I'm Spanish and my English is far from perfect. What's poaching? :)

xabi

Answering a question where a comment might be the answer
(poaching is when people go hunting where they are not allowed)

Michel

Ok, sorry. It was a crossposting. Sorry.

xabi