It took me an active hour or so to get this code segment done for my own Play by Post game and I was hoping we could get it implemented into the actual die roller for combat. Currently the roller only looks at your mods and if the last roll was a critical hit, this new code segment automatically checks that same attack roll against a target you type in and will also do a fumble check.

You would only need to add one more field into your Die Roller GUI and change the output code to what I have included below. Please note that I have not matched my fields to what your current code is using for variables.
The benefit of this new code is that if the previous roll was a failure the damage would show up as "0".
Downside is it requires you to know the target numbers.

Attack: [roll]1d20+[AMOD][/ roll] 
Damage: [roll]if([roll:-1:fumble], =1,0,if([roll:-1],<[TARGET],0,if([roll:-1:critical],=1,2{[DAMAGE]}.expand(),[DAMAGE])+[DMOD]))[/ roll] 

The dice roller pop up has the option to make a combat roll: you can choose advantage, you can add the bonus/penalty, crits show green and auto-re-roll your damage and crit fails are shown in red, but still show result in case you need to know (like for skill checks). 

Even with the basic pre-built dice roller it does everything you need for an attack roll. I'm not sure what it is you're trying to do that it already doesn't.

Attack: 17 Damage: 10

What I'm trying to do is have it say 0 damage when it misses.

Isn't that largely unnecessary since most players who roll will not know the monster AC and most DMs have a quick list of the player ACs? 

Seems a very niche thing, I'd rather the Devs focus on something more useful to the wide audience.Like finally implementing Spells of the Mark features, Class Variant features, and similar things they are quite behind on, and the making rolls from the character sheet dice function they have planned, and so on. 

I don't need a comparative function in my dice rolls - I can just do that in 2 seconds using simply my brain, I just need a dice roller to roll dice, and the one the forums have does that and more. 

If you didn't notice, the work is done for them with the code I posted above. It is now a 5 minute job (7 minutes if you include updating the GitHub).

There has been little effort put into their PbP tools and this would help with some of my players to make it more plug and play.

Lastly, the teams working on the forums are not the same teams working on bringing in UA, updating the books.

Quote from K_Manderscheid >>

 

Lastly, the teams working on the forums are not the same teams working on bringing in UA, updating the books.

 
And you know this, how?