In Foxit PDF Editor, a combo box can be set up so that it can export value to a text field. This could be done via JavaScript:
1) Create a combo box, name it as ct; Create a text field, name it as c1;
For combo box ct, items have been added with export values; Item Y with the export value of Y and Item N with the export value of N.
3) Right-click on the text field to open Properties > Calculate > Custom calculation script > Edit, then copy the following script:
var c1=this.getField("ct").value;
event.value=c1;
4) Click close.