Calendar - Dropdowns Containing Months And Years

I'm trying to get a pair of drop down menus to appear on the screen, one containing months, and one containing years. I know the one containing years works, since it hasn't been changed at all since it was working, but the month box used to be a textbox. I tried to convert it over to drop down box using the same code as the year box, but it hasn't seemed to work.

<script language="Javascript">
var m1 = January;
var m2 = February;
var m3 = March;
var m4 = April;
var m5 = May;
var m6 = June;
var m7 = July;
var m8 = August;
var m9 = September;
var m10 = October;
var m11 = November;
var m12 = December; .....

document.write('<select name="selYear">');
for (var x=0; x <= 10; x++ ) {
if(x != 5){
document.write('<option value="' + x + '">' + yearArray[x] + '</option>');
}else{
document.write('<option value="' + x + '" selected>' + yearArray[x] + '</option>');
}} document.write('</select>');
</SCRIPT>