Question Webgl Build Failed

So I am creating a unity webgl game. I want my script to know at runtime if the webgl game in the browser is on Desktop or A mobile device so I used the following method:
-I created a file named "MyPlugin.jslib" in Assets/Plugins/webgl/MyPlugin.jslib
that isn what i wrote inside this file:

var MyPlugin = {
IsMobile: function()
{
return Module.SystemInfo.mobile;
}
};
mergeInto(LibraryManager.library, MyPlugin);

-Then I added following to my unity script:

using System.Runtime.InteropServices;
#region WebGL is on mobile check
[DllImport("__Internal")]
private static extern bool IsMobile();
public bool isMobile()
{
#if !UNITY_EDITOR && UNITY_WEBGL
return IsMobile();
#endif
return false;
}
#endregion

I used bool isMobile() to Check if the device on which my webgl game is running is a mobile device or not. Everything worked fun in editor. But when I sarted to build the game. The build failed and these errors showed:

'Library\Bee\artifacts\WebGL\build\debug_WebGL_wasm\build.js: undefined symbol: IsMobile (referenced by top-level compiled C/C++ code)
UnityEditor.BuildPlayerWindow:BuildPlayerAndRun ()'

'Building Library\Bee\artifacts\WebGL\build\debug_WebGL_wasm\build.js failed with output:
error: undefined symbol: IsMobile (referenced by top-level compiled C/C++ code)
warning: Link with `-s LLD_REPORT_UNDEFINED` to get more information on undefined symbols
warning: To disable errors for undefined symbols use `-s ERROR_ON_UNDEFINED_SYMBOLS=0`
warning: _IsMobile may need to be added to EXPORTED_FUNCTIONS if it arrives from a system library
Error: Aborting compilation due to previous errors
emcc2: error: '"C:/Software/unity 2021 new/2021.3.11f1/Editor/Data/PlaybackEngines/WebGLSupport/BuildTools/Emscripten/node/node.exe" "C:\Software\unity 2021 new\2021.3.11f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten\emscripten\src\compiler.js" C:\Users\Hp\AppData\Local\Temp\tmpjf_g3fkj.txt' failed (1)
UnityEditor.BuildPlayerWindow:BuildPlayerAndRun ()
'
Please help resolve this and if there is some other way from which I can check device type then that will work too. Thanks

 

It looks like you're doing everything correctly.

Is your plugin marked (in the inspector) to be included with WebGL?

That should be automatic but since you lowercased the

Plugins/webgl/

directory, maybe it didn't get set?

 

Yes the webgl is check. and my project is also on webgl platform

 

Like I said, it really looks like you're doing it all correctly then.

Perhaps try reimport all??

Here was the guide I followed and it worked fine:

https://va.lent.in/opening-links-in-a-unity-webgl-project/

Perhaps try it in a blank project???