Placing in another invisible iframe. (#3)
Placing in another invisible iframe. (#3)

* Update BackgroundFormSender.js

Let theRuntime be class scope.

* Update BackgroundFormSender.js

Improve usage comment.

* Update BackgroundFormSender.js

Place all generate HTML element inside another invisible iframe.

* Improve comments.

ColorfulCakeChen/query-submit-canvas,ColorfulCakeChen/query-submit-canvas