That's not HTML but BBcode. Allowing users to input HTML is a security breach.

The line after For(VAR,START,END) will hold the value of END-VAR for the current iteration. You can use this to optimize if you'd like, just keep in mind that this could potentially change in the future.

I can't say I've seen optimizations involving the use of this value... I have, however, made many optimizations using For(CONST), as this doesn't even affect HL. But be wary that For(VAR/EXPR) will load VAR/EXPR into HL at the start of the first iteration, but not after that.

You can't use a variable in a conditionnal comment. It is described in the readme that the argument must be a constant (or a test involving only constants, which is a constant in some way).

It can be useful for example (other examples can be found but I give this one) if you want to make two versions of your program: one for regular 83+ and one for the 15 MHz calcs. Then just do your code like that:

.PROGRAM
XXX→°Model

<put some code here>

...If °Model=83
<put here the code for the regular 83+>
...Else
<put here the code for 15MHz models>
...End

<put some code here>

Then, to compile the 83+ version, replace XXX with 83 and compile, and to compile the 15MHz version, replace XXX with 84 and compile. If °Model=83, only the code for the regular 83+ will be parsed, and the contrary if you put 84.
And since the compiler tests °Model when compiling and not when launching the program, you can't use a variable there.

Alright, I need some help with appvars.  I don't actually have my calc right now, but this is about what my code looks like.
getcalc("appvMAP,10")->A
For(X,0,9)
0->{A+X}
End
1->{A}
For(X,0,9)
Output(0,0,{X+A}>Dec)
End
Obviously not complete or optimized, I'm just trying to get used to appvars.  My issue is that I've stored 0s and 1s to the appvar, yet it outputs values from between 0 and 255.  Any ideas why its doing this?  I assume I'm either writing to it incorrectly or reading incorrectly, but I can't figure it out.

Hmm... being able to see the real code could be helpful. I believe there are some copying errors in that code, like the size argument of GetCalc() being inside the quotation marks and the value outputs all overwriting each other.

If by outputs overwriting eachother you mean they all go to 0,0, than yea they do.  I just stuck a pause 500 in there so I could see each number.  As for the quotation marks, I just realized I didn't have them like that, not sure why I thought I did...

Also, that doesn't solve any problem, but you may want to check the Fill command out instead of using a For loop to set a bunch of bytes at 0.
Now your code seems to work on Wabbit (once I put the quotes at the right place), I don't see any problem, it displays a 1 then zeroes.
Also be sure that the appv is the appv token, and not a "a" followed by a "p", ...

*Facedesk*. Realized in math today that I had been reading the code as I thought I wrote it, not as I actually did, silly typos fixed, and it works well now.  Thanks for attempting to help though

On an unrelated note, is there a better way to handle input from getkey than a bunch if if/elseif?