disable/enable combobox with onpick option?

I have set a combobox, “zColor” to be disabled. However, I want to enable “zColor” once a value from a different combobox, “zSize” has been selected.



My approach was to use the onpick option:



Size 1 [ x ]



Any suggestions?

It can be done as

comboA.attachEvent(“onChange”,function(){
    if (comboA.getActualValue()==“1”)
       zColor.disable(false);
    else
       zColor.disable(true);
})