How To Run HTML Pages In Thunkable App:
From the looks of things in your script , all you have to do is insert
data:text/html, (include that comma at the end) just before the
<html> tag in the first part of the
data: has been specified in the URL world to pump data into the web page as if it existed on the internet. Works offline too!
Bear in mind that when you run your script again and again, the webpage will refresh causing any inputs on a page to be cleared.
Create App in Your Language:
You can create app in any lanuage…But only the thing is you can not create app coding in your own lanuguage. At the same time You can develope them in HTML pages, then you can get the app format using webviewer componet by adding above mentioned methods.
To Show Your HTML page You Should add below mentioned code in your content.
i.e data:text/html your HTML