usage is now splitFrames(framedata, casttime, dwdelay, firsthit, numoffsets, showindividualwields, enabledualwieldcast, showdrops)

splitframes.js

function splitFrames(frames, cast, dwdelay, fst, offsets, showwields, enabledw, enabledrops) {
  var out = [];
  var firsthits = [];
  for (var i = 0; i <= offsets; i++) {
    var newhits = splitFramesOffset(frames, cast, dwdelay, fst, i, firsthits, showwields, enabledw, enabledrops);
    if (firsthits.length == 0)
      firsthits = newhits[0];
    out = out.concat(newhits);
  }
  return out;
}

function splitFramesOffset(frames, cast, dwdelay, fst, offset, hits, showwields, enabledw, enabledrops) {
  var CHAIN_BREAK_LIMIT = 19;
  var first = parseInt(cast) + parseInt(fst) + parseInt(offset);  
  var hitsoffset = -1;
  for (var i = 1; hitsoffset == -1 && i < hits.length; i++) {
    if (first < hits[i] && first >= hits[i - 1]) hitsoffset = i;
  }
  

  var fs = frames.split(",").map(function(x) { return parseInt(x) });
  
  var outframes = [];
  outframes.push(first);
  for (var i = 0; i < fs.length; i++) {
    outframes.push(fs[i] + (i == 0 ? first : outframes[i]));
  }

  var wield2 = parseInt(cast) + first + parseInt(dwdelay);
  var wield2i = -1;
  for (var i = 1; wield2i == -1 && i < outframes.length; i++) {
    if (wield2 < outframes[i] && wield2 >= outframes[i-1]) wield2i = i;
  }

  var outframes2 = [];
  var w2shift = wield2i == -1 ? outframes.length : (wield2i - 1);
  for (var i = 0; i < w2shift; i++)
    outframes2.push("");

  outframes2.push("");
  outframes2.push(wield2)
  var w2start = outframes2.length - 1;
  for (var i = 0; i < fs.length; i++) {
    outframes2.push(fs[i] + (i == 0 ? wield2 : outframes2[w2start + i]));
  }

  var outframes3 = outframes.concat(outframes2.filter(function(x) { return enabledw && x != "" }));
  outframes3.sort(function(a,b) { return a - b });
  var hitshift = hitsoffset == -1 ? 0 : Math.max(0,hitsoffset-1);
  for (var i = 0; i < hitshift; i++) {
    outframes.unshift("");
    outframes2.unshift("");
    outframes3.unshift("");
  }

  outframes.unshift(offset);
  outframes2.unshift(offset);
  outframes3.unshift(offset);
      
  if (offset != 0) {
    for (var i = 1; i < outframes3.length; i++) {
      if (outframes[i] != "") {
        if (enabledrops && (outframes3[i] < hits[i-1] || outframes3[i] > hits[i])) {
            outframes3[i] = "(" + outframes3[i] + ")";
        } else if (enabledrops && Math.abs(outframes3[i] - hits[i-1]) > CHAIN_BREAK_LIMIT)
          outframes3[i] = "*" + outframes3[i];          
        else if (enabledrops && Math.abs(outframes3[i] - hits[i]) > CHAIN_BREAK_LIMIT)
          outframes3[i] = outframes3[i] + "*";
      }
    }
  }
  return enabledw && showwields ? [outframes3, outframes, outframes2] : [outframes3];
}