Hi @lasselauch sorry for the late reply, I asked about the developer responsible for it.
On Windows we use the WebView control of the last iteration of iexplore MS shipped for 8.1 - Internet Explorer 11 (user-agent ID: "Trident").
It supports >most< things other modern browsers do, but sadly not everything...
Especially the JS support has become a problem since IE11 is missing parts of the ECMA 6 standard and needs 'polyfills' to emulate those.
Many JS frameworks / libraries don't offer IE11 compatibility and instead rely on the developer to add those polyfills themselves.
One of the improvements IE11 received back then was the developer console+tools so the user could use those to track > down the JS issues and resolve them."
I also forwarded your request about the ability to disable Javascript, but so far nothing planned atm, so the only workaround I see is either fix your javascript framework (maybe a huge task) or you can disable your javascript based on the user agent and if it's an IE11.
Hope this help,
Cheers,
Maxime.