Hello there,
id like to know if there is a script like NativeUI_Lua thats using FiveM natives to make an extremely smooth and lag free UI like in GTA / GTA:O but for bigger applications like e.g. the GTA:O nightclub Computer.
I do not like using HTML in FiveM as its the first thing that starts lagging whenever theres a small FPS drop, sometimes it even just lags randomly…
Or alternatively if theres any way i can make my HTML performance better!
Thanks!
Marvin 
Your best option is to create it in HTML, you will thank yourself later as it’ll be easier to work with.
In regards to your HTML randomly lagging, the culprit will most definitely be a JS file you’ve included (or some other file that the HTML is relying on).
A standalone HTML page is nothing but a static drawing and once it’s been received from the server, will not affect performance whatsoever - so to ‘fix’ your HTML/UI, take a look at the corresponding JS files and any other includes - check for loops and while statements as they usually impact performance the most.
These screens are made with scaleforms, a lot of them are undocumented and you’ll need to go through decompiled GTAV scripts to see how they work.
Unless you have quite a long experience in programming I wouldnt recommend it since as Mojito says the scripts you would need to use as a “template” / “example” are not documented and will most likely be really hard to understand.
I would recommend just using HTML + CSS with normal javascript, vuejs or jquery.