awmt102

I had exactly the same problem and i found a way to do it:

first of all you need to declare these three functions:

function populateBox(oBox, nIndex, aArray){

for (var i = 0; i < aArray[nIndex].length; i = i + 1){

oBox.options[oBox.options.length] =
new Option(aArray[nIndex][i], aArray[nIndex][i]);
}
}

function clickcombo1(elem,array1){
clearcombo(document.f1.combo2);

populateBox(document.f1.combo2,
elem[elem.selectedIndex].value, array1);
return true;
}

function clearcombo(elem){
var i;
for (i = elem.options.length; i >= 0; i--) elem.options[i] = null;
elem.selectedIndex = -1;
}


You then put in your form as required. Mine looked something like this:

<select NAME="combo1" SIZE="5" ONCHANGE="clickcombo1(this,ArrayToPopulateSecondList)"></select>

<select NAME="combo2" SIZE="5"></select>

Further in the file you must also include this line:

populateBox(f1.combo1,'0',ArrayToPopulateFirstBox);

Where f1 is the name of the form that combo1 appears in.

At this point i will describe how this actually works:

Each select box is populated by a javascript array, i.e. each element in the array is a different option in the box. The second box is populated using another array, although this time it is a two dimensional one. the first dimension is exactly the same as the array that populates the first box. The second dimension contains the data you wish to appear in the second box when the first dimension's value is the same as the first select boxes value.

That is prob quite confusing so here is a simple example (in fact it is exactly the example i have used on my site).

There are a number of text files available on my site. They are made up of different languages, some french, some english, some spanish etc. The idea is that you select the language you wish to view download these particular files in, and the second box is populated with only the files in this language. (The language<->File info is held in a database).

So the first array is simply an array of the languages available:

array[0]=English
array[1]=French
array[2]=Spanish

The second array is 2 dimensional:

array2[English][0]=FirstEnglishFile
array2[English][1]=SecondEnglishFile
array2[French][0]=FirstFrenchFile
array2[French][1]=SecondFrenchFile
array2[French][2]=ThirdFrenchFile
array2[Spanish][0]=OnlySpanishFile

So now, when you select English, the second box will show:

FirstEnglishFile
SecondEnglishFile

You must note that the first array needs only be one dimensional to hold the data, however, if you try and pass a one-dimensional array into the function populatebox() it will complain. This is because it is designed to cope with populating the second box as well, which uses a 2D array. For this reason the first array must also be 2D, but only one of the dimensions is actually used. i.e the first array will be:

array[0][0]=English
array[0][1]=French
array[0][2]=Spanish


So thats how its done in javascript and html, if you have any probs understnading then let me know, however it looks like u are using php (as i did). This causes some small hassle because php arrays are different from javascript arrays. I will explain in another post (in just a few minutes) how to do that.