Does "1e-6" like stuff exist in here?

Following some JavaScript tutorial, I stumbled upon a value with "1e-6", do those stuff exist here?

Yes, though I don't know if it works if you do 1e-6. You would just do it like this:

1*10^6
1*10^-6

Basically, the 1e-6 is just a way to write scientific notation.