Without JavaScript, the variant selector uses simple select fields. If that's what you need, you could simply deactivate the variant selector module by removing the following line from "files/merconisfiles/themes/theme10/lsjs/app/app.js"
With JavaScript the basic variant selector form is overwritten by the variant selector module. You can modify the variant selector module, if you like. Just take a look at the module here: files/merconisfiles/themes/theme10/lsjs/app/modules/merconis/variantSelector