Go4Expert - problem displaying the options in selectbox while creating it dynamically in opera9.2

i have two select boxes based on the selected value in one select box it should display the maximum options in the other select box.
i used javascript onClick for the first time it displays correct values again when i go back and change the value in the 1st selectbox the 2nd select box display previous values only.it works in all the browsers except opera.
my code is

Code:

function CalBasedMaxVal(selVal,changedVal,maxiVal,DefVal)

{

var CalBasedSelValue=selVal.selectedIndex+1;

var defaultText = '-['+lang_text_ary['default']+']';

var optionName;

while (changedVal.options.length)

{

changedVal.remove(0);

changedVal.options[0] = null;

}

for (var i=1; i<=maxiVal; i++)

{

if(i==DefVal)

{

optionName = new Option(i+defaultText, i, false, true);

}

else

{

optionName = new Option(i, i, false, false);

}

changedVal.options[changedVal.length] = optionName;

}

}