Button's OnClick event can't call OnChange function of another DropDownList

Hi expert,
I am trying to use Classic version of CalendarXP (www.calendarxp.net/). Its ok. But I am facing another problem.
You know Classic version of CalendarXP has three DropDownLists(for Day, Month and Year) and one Button. When you click on button, a calendar pop is gererated. If you select a date from calendar pop, day will be shown on Day dropdownlist, month will be shown on Month DropDownList and year will be shown on year DropDownList. Each dropdownlist has onChange="if(self.gfPop)gfPop.updateHidden(this)". This function updates hidden text box, in where date is contained.
Problem is:
Before using CalendarXP control, I used a function  calculate(frmED,(passissDate_day.value),(passissDate_mon.value),(passissDate_year.value)) OnChange event of passissDate_year DropDownList. When I click on passissDate_year DropDownList, this OnChange function works. When I click on its button, calculate function doesnt work, but gfPop.updateHidden(this) works.


<select name="passissDate_year" class="listBox100" id="passissDate_year" style="width:60px;" onChange="calculate(frmED,(passissDate_day.value),(passissDate_mon.value),(passissDate_year.value))">
                  <script>document.write('<option value="-">year-');for(var i=1980;i<=2030;i++) {document.write('<option value="'+i+'">'+i)}</script>

<INPUT name="popcal4" width="10" onclick="if(this.blur)this.blur();var fm=this.form;if(self.gfPop){gfPop.fStartPop(fm.passissDate,fm.passexpDate, this);calculate(frmED,(passissDate_day.value),(passissDate_mon.value),(passissDate_year.value));}" type="button" value="..." class="vbtn">

Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Are you getting any javascript errors when you click that?  It's possible that this calculate function is already defined within the CalendarXP control.  Could you try renaming your function?

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.