How can I program the button to create a random background? [duplicate]

So I’m working on a background generator that allows you to pick two colors for a gradient.
I would like to program the random button to provide a random background.
I know in order to do this, the button would need to generate 3 random numbers between 0-255 for each color, for a total of 6 random numbers.
Then, I would use DOM manipulation to edit the input.
However, I have no idea how to even begin coding this.

Currently, I have on my index
<button onclick="Random()">Random!</button>

And I’m lost on what I need to create the
function Random()

I’m a complete newbie to JavaScript, so please bear with me, thank you!