Very little obfuscation occurs in an html app unless you do your own obfuscating.
If you use app.HttpRequest() directly in the .html file of your html project, only the method name will be obfuscated
You can, however, add a .js file to your project beside the main .html file.
You then load that into your html code using app.Script()
When you build your apk with obfuscation turned on, the .js file will be obfuscated as if it were part of a native app.
The attached minimal SPK shows how the files would be organized. inc.js holds the app.HttpRequest code.
The html code includes the JavaScript
app.Script( "inc.js" )
doAjax()