DHTMLCOMBO

I’m using z.getSelectValue()

i need to get the value in java form to save it.

Thanks

The correct method name is
    z.getSelectedValue
it return value, if it was selected from the list of option, combo also supports
    z.getActualValue
which returns value for both selecting existing or typing new one

The both method operates with client side code, so you need any custom way to send such data to server side.
If combo was created inside form - it will send value as part of form during submit.