Inserting a variable from javascript into html?

[Messiah Khan]

I need to get a javascript to insert a variable into a html file. I've managed to get it to work in a form, but how do I do it (or is it even possible) in order to place the variable into a dropdown selection menu?

<select name="item_framing">
<option value="1_UF">Unframed (+£0)</option>
<option value="2_MN">Mounted (+£x)</option>
<option value="3_FR">Framed (+£x)</option>
</select>

Is the code, and 'x' is where I want to place the variable depending on what has been selected in another dropdown menu. Any ideas?

 

[Messiah Khan]

Build the second dropdown dynamically with javascript after an event on the first drop down.

Cheers big ears. Got that sorted and linked up to Paypal. It's all working nicely now.