Simplify FHP.js and use code supporting modern browsers

[Weredime]

We currently implement the fetch standard, which is present starting Chromium 42 and Firefox 39.
In FHP.js, we can really simplify it a LOT, and use better code practices supported in these versions, such as:

• document.createElement instead of Element.innerHTML - XSS could be a thing, but moderation is implemented in the main website. Really, you should just use .innerText, It's supported in most browsers.
• Use const or let instead of var. The declaration var isn't really good (search it up on google, there are loads of things).
• Use for .... of .... iterators instead of for (j = 0; j < .... iterators. It's supported in most browsers, and we really don't need the index of the member in the array.
• We shouldn't keep calling document.getElementById(string) every single time we need to update it in the same section of the code. We should just declare a variable!

I hope you take this into consideration, as this would introduce new JavaScript programmers to better solutions for code, instead of old ones.

[gosoccerboy5]

document.createElement in FHP.js would make it a lot more verbose, and I don't think XSS is as much of a risk for such a simple, relatively low-traffic site like this

[penguinmoose]

Yeah, I’ve heard that let is sometimes better than var

[penguinmoose]

And I always use const for things that don’t change - it’s just better (it doesn’t let you change it I think) in my opinion.

[gosoccerboy5]

does it really matter in the case of this repo tho?

[penguinmoose]

@gosoccerboy5 It probably won't impact the actual site. I guess it's just a code improvement.