RE: How to auto populate a field value from entity form to HTML web resource section (Note Entity adx.annotations.html)?
Hi,
I am not sure how you designed your web resource and which elements you have on it. But the logic is simple.
Add a function to OnChange event of your VehicleType field.
On your onchange event, find your elements of your webresource. It should be in either window's context of your browser. Or you can search through elements by using JQuery.
In addition, You need to add your web resource to form libraries, JQuery as well if you are going to use. Open your form editor, click form properties.
Once your webresource library and your web resource that contains the function for OnChange event added form libraries, you should be able to see your elemets of the webresource.