webgl load in iphone very slow , and UGUI item squeezed in center

i bulid webgl , and host in iis server android load the webgl has no problem bug

if use iphone to load webgl , need very time , ro stuck at about 90%

if i success use iphone load webgl , the UI item well all squeezed in center

is UnityWebGL not support iphone? i do somethine wrong ro lost somethine?

Solution

I can just understand that WebGl is very slow on iOS or crashes sometimes, right?

Well, the bad news is that Unity says that mobile browsers aren't supported at all.
See this answer

They recommend to use WASM export instead of asm.js and personally I think that you should keep the app as small as possible. Reduce the amount of data to minimum. Also switch off as many internal packages as you can using the package manager.