Unique 6 Digit Numeric ID Javascript without Repeat

I am looking for a Javascript Code that can automatically generate Unique 6 Digit Numeric ID e.g. 123456. It should not repeat the same ID again ever. It should be generated automatically when I reload the page. Can someone please help me for this ?

I have already tried the timestamp code but this does not fit for what I am looking for.

I am not a developer or coder, please give me a complete code.

Best wishes,

Khawar Khalid