Make field editable when checkbox is checked, otherwise given read-only value

Question

I'm attempting to make a fillable PDF form, from and existing document, using  Acrobat Pro that does the following:
Purpose of form is to provide customer a way to agree to purchase a custom artwork.
The artwork has a base price, ArtworkPrice. (The ArtworkPrice field is editable)
The customer can choose to include a picture frame. (AddFrame checkbox 'Yes'.)
Choosing 'Yes' to add a frame adds an amount.  (The FramePrice field is editable only if AddFrame checkbox is checked)
Otherwise, Leaving AddFrame unchecked fills the FramePrice field with a value of 0.00.
The TotalPrice is calculated as the sum of the ArtworkPrice and the FramePrice fields. (The TotalPrice field is read-only)
So...this part of the form looks essentially of like this:
AddFrame? [  ] Yes
ArtworkPrice $__________   +  FramePrice $__________ = TotalPrice $__________
The FramePrice field must be 0.00 (and not editable) at all times unless the AddFrame checkbox is selected.
How can I do this?

Answer 1

Add this code to the MouseUp event of AddFrame:
if (this.getField("AddFrame").value=="Off") {
this.getField("FramePrice").value = 0;
this.getField("FramePrice").readonly = true;
} else {
this.getField("FramePrice").value = "";
this.getField("FramePrice").readonly = false;