Dual Drop Down

I have a script that is a double drop down menu. One side is year - other is months. My problem is. I have to reset the year every time I want to change months. I would like to be able to select say year 2009 and then choose jan - feb etc or the same for 2010 and 2011 etc. Can anyone tell me how to do this.

Here is the script I have


<script language="javascript">

<!--//

//new Option("text","value")

//this code changes menus







function nullOptionsDMA(aMenu){

var tot=aMenu.options.length

for (i=0;i<tot;i++)

{

aMenu.options[i]=null

}

aMenu.options.length=0;

}



function MySubjectDMA0(aMenu){

nullOptionsDMA(aMenu)



with (aMenu){



//Rewrites the text and values

options[0]=new Option("Select a page","none");

options[1]=new Option("January","9jan.html");

options[2]=new Option("Feburay","9feb.html");

options[3]=new Option("March","9mar.html");

options[4]=new Option("April","9apr.html");

options[5]=new Option("May","9may.html");

options[6]=new Option("June","9jun.html");

options[7]=new Option("July","9jul.html");

options[8]=new Option("August","9aug.html");

options[9]=new Option("September","9sep.html");

options[10]=new Option("October","9oct.html");

options[11]=new Option("November","9nov.html");

options[12]=new Option("December","9dec.html");

options[0].selected=true





}

}

function MySubjectDMA1(aMenu){

nullOptionsDMA(aMenu)



with (aMenu){



//Rewrites the text and values

options[0]=new Option("Select a page","none");

options[1]=new Option("January","0jan.html");

options[2]=new Option("Feburay","0feb.html");

options[3]=new Option("March","0mar.html");

options[4]=new Option("April","0apr.html");

options[5]=new Option("May","0may.html");

options[6]=new Option("June","0jun.html");

options[7]=new Option("July","0jul.html");

options[8]=new Option("August","0aug.html");

options[9]=new Option("September","0sep.html");

options[10]=new Option("October","0oct.html");

options[11]=new Option("November","0nov.html");

options[12]=new Option("December","0dec.html");

options[0].selected=true





}

}

function MySubjectDMA2(aMenu){

nullOptionsDMA(aMenu)



with (aMenu){



//Rewrites the text and values

options[0]=new Option("Select a page","none");

options[1]=new Option("January","11/jan.html");

options[2]=new Option("Feburay","11/feb.html");

options[3]=new Option("March","11/mar.html");

options[4]=new Option("April","11/apr.html");

options[5]=new Option("May","11/may.html");

options[6]=new Option("June","11/jun.html");

options[7]=new Option("July","11/jul.html");

options[8]=new Option("August","11/aug.html");

options[9]=new Option("September","11/sep.html");

options[10]=new Option("October","11/oct.html");

options[11]=new Option("November","11/nov.html");

options[12]=new Option("December","11/dec.html");

options[0].selected=true





}

}

function MySubjectDMA3(aMenu){

nullOptionsDMA(aMenu)



with (aMenu){



//Rewrites the text and values

options[0]=new Option("Select a page","none");

options[1]=new Option("9January","12/jan.html");

options[2]=new Option("Feburay","12/feb.html");

options[3]=new Option("March","12/mar.html");

options[4]=new Option("April","12/apr.html");

options[5]=new Option("May","12/may.html");

options[6]=new Option("June","12/jun.html");

options[7]=new Option("July","12/jul.html");

options[8]=new Option("August","12/aug.html");

options[9]=new Option("September","12/sep.html");

options[10]=new Option("October","12/oct.html");

options[11]=new Option("November","12/nov.html");

options[12]=new Option("December","12/dec.html");

options[0].selected=true





}

}

/* ####################### goDM() ####################### */



function goDMA(aMenu){

if (aMenu.options.value!="none")

{

location=aMenu.options[aMenu.selectedIndex].value

}



}



/* ####################### setUp ####################### */



function setUpDMA(){

with (document.formDoubleMenuDMA) {

if (menuSubjectsDMA.selectedIndex==0){

menuSubjectsDMA.options[0].selected=true

menuFilesDMA.options[0].selected=true

}



if (menuSubjectsDMA.selectedIndex==1)

MySubjectDMA0(menuFilesDMA)

if (menuSubjectsDMA.selectedIndex==2)

MySubjectDMA1(menuFilesDMA)

if (menuSubjectsDMA.selectedIndex==3)

MySubjectDMA2(menuFilesDMA)

if (menuSubjectsDMA.selectedIndex==4)

MySubjectDMA3(menuFilesDMA)



}

}



/* ####################### changeFiles ####################### */



function changeFilesDMA(){

aMenu=document.formDoubleMenuDMA.menuSubjectsDMA

aMenu2=document.formDoubleMenuDMA.menuFilesDMA

with (aMenu){



switch (selectedIndex) {

case 0:

aMenu2.options.length=0;

aMenu2.options[0]=

new Option("Pages appear here","none")

aMenu2.options[0].selected=true;

history.go(0)

break

case 1:

MySubjectDMA0(aMenu2)

aMenu2.options[0].text="Month"

break

case 2:

MySubjectDMA1(aMenu2)

aMenu2.options[0].text="Month"

break

case 3:

MySubjectDMA2(aMenu2)

aMenu2.options[0].text="Month"

break

case 4:

MySubjectDMA3(aMenu2)

aMenu2.options[0].text="Month"

break



}

}



}

//-->

</script>






<body>





<form name="formDoubleMenuDMA" >



<p>



<!-- This menu holds the subjects-->

<select name="menuSubjectsDMA" onChange="changeFilesDMA()">

<option value="none" >Year

<option value="">2009

<option value="">2010

<option value="">2011

<option value="">2012

</select>

<!-- this menu holds the files to go-->

<select name="menuFilesDMA" onChange="goDMA(this)" style="width:80">

<option value="none"> Month







</select>







<p>



</form>