You cannot stop people from viewing your frontend website source code. The browser needs to know the code to be able to display to the user. If you're worried about people stealing your html and stealing some idea, you can attempt to obfuscate code by making it difficult to read.
If you are trying to hide user data though, you shouldn't have that in the frontend to begin with. Any and All sensitive data should only be on a secured backend, and the frontend should query that data.
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You cannot stop people from viewing your frontend website source code. The browser needs to know the code to be able to display to the user. If you're worried about people stealing your html and stealing some idea, you can attempt to obfuscate code by making it difficult to read.
If you are trying to hide user data though, you shouldn't have that in the frontend to begin with. Any and All sensitive data should only be on a secured backend, and the frontend should query that data.