Help! I need sombody! HELP! Anybody... That knows sheet building...

So, I'm trying to build a custom ability layout. I have a bunch of fields that have specific data in them, and that's fine.  But I then want a special blank field that they can put their dice into plus whatever additional modifiers, must like if they were to do [[ ((1D6+5)*3)/2+1D8..... ]] I don't want to get heavy into Java if I don't have to. I just need a field that will grab whatever is input into that and include it in the roll button function (which includes the other stuff which is basically a bunch of attr_xxxxxx_xxxx stuff.

That shouldn't need any javascript, just make the field a text or textarea input instead of a number input.  That attribute can then be called within a roll button macro just like any other attribute.