Integrating Javascript Calendar

[possi83]

Hi,

I am trying to integrate a Javascript Calendar that i got the code from this website:
http://www.garrett.nildram.co.uk/calendar/scw.htm#available

currently there is a field on my site that when you click on, it calls up the calendar 'scwShow(this,event);' and you can select a date which then fills the field with the date you selected. coded as below;

<input onclick='scwShow(this,event);' value='12-Sep-2006' />

Instead of having this one input field, I would like to replace it with two fields, Ie: date and month with drop down lists. - which i have done already.

But the question i have is how can i get the calander to fill in these two fields with date and month rather than the above one input field?
ie: I would like it to work like the calanders you get on sites when you're booking a hotel room.

This is an example of my month field code;

<label>
<select name="Arrivmonth" id="Arrivmonth">
<option>Jan</option>
<option>Feb</option>
<option>Mar</option>
<option>Apr</option>
<option>May</option>
<option>Jun</option>
<option>Jul</option>
<option>Aug</option>
<option>Sep</option>
<option>Oct</option>
<option>Nov</option>
<option>Dec</option>
</select>
</label>

Your help is greatly appreciated :)