How can I reliably subsort arrays using DOM methods?

OK. So, as you've discovered, your problem is that the default JavaScript sort is not guaranteed to be stable. Specifically, I think that in your mind it works like this: I'll sort by blueness, and then when I sort by greenness the sorter will just move entries in my array up and down but keep them ordered by blueness. Sadly, the universe is not so conveniently arranged; the built-in JS sort is allowed to do the sort how it likes. In particular, it's allowed to just throw the contents of the array into a big bucket and then pull them out sorted by what you asked for, completely ignoring how it was arranged before, and it looks like at least some browsers do precisely that.

There are a couple of ways around this, for your particular example. Firstly, you could still do the sort in three separate calls, but make sure those calls do the sort stably: this would mean that after sorting by blueness, you'd stably sort by greenness and that would give you an array sorted by greenness and in blueness order within that (i.e., precisely what you're looking for). My sorttable library does this by implementing a "shaker sort" or "cocktail sort" method (http://en.wikipedia.org/wiki/Cocktail_sort); essentially, this style of sorting walks through the list a lot and moves items up and down. (In particular, what it does not do is just throw all the list items into a bucket and pull them back out in order.) There's a nice little graphic on the Wikipedia article. This means that "subsorts" stay sorted -- i.e., that the sort is stable, and that will give you what you want.

However, for this use case, I wouldn't worry about doing the sort in three different calls and ensuring that they're stable and all that; instead, I'd do all the sorting in one go. We can think of an rgb colour indicator (255, 192, 80) as actually being a big number in some strange base: to avoid too much math, imagine it's in base 1000 (if that phrase makes no sense, ignore it; just think of this as converting the whole rgb attribute into one number encompassing all of it, a bit like how CSS computes precedences in the cascade). So that number could be thought of as actually 255,192,080. If you compute this number for each of your rows and then sort by this number, it'll all work out, and you'll only have to do the sort once: so instead of doing three sorts, you could do one: sorter.sort(function(a,b) { return (a.red*1000000 + a.green*1000 + a.blue) - (b.red*1000000 + b.green*1000 + b.blue) } and it'll all work out.

Technically, this is slightly inefficient, because you have to compute that "base 1000 number" every time that your sort function is called, which may be (is very likely to be) more than once per row. If that's a big problem (which you can work out by benchmarking it), then you can use a Schwartzian transform (sorry for all the buzzwords here): basically, you work out the base-1000-number for each row once, put them all in a list, sort the list, and then go through the sorted list. So, create a list which looks like [ [255192080, <table row 1>], [255255255, <table row 2>], [192000000, <table row 3>] ], sort that list (with a function like mylist.sort(function(a,b) { return a[0]-b[0]; })), and then walk through that list and appendChild each of the s onto the table, which will sort the whole table in order. You probably don't need this last paragraph for the table you've got, but it may be useful and it certainly doesn't hurt to know about this trick, which sorttable.js also uses.

I would approach this problem in a different manner. It appears you're trying to reconstruct all the data by extracting it from the markup, which can be a perilous task; a more straightforward approach would be to represent all the data you want to render out to the page in a format your programs can understand from the start, and then simply regenerate the markup first on page load and then on each subsequent sort.

For instance:

var colorsData = [  {    keyword: 'mediumspringgreen',    decimalrgb: {      r: 0,      g: 250,      b: 154    },    percentrgb: {      r: 0,      g: 98,      b: 60.4    },    hsl: {      h: 157,      s: 100,      l: 49    }    hex: '00FA9A',    shorthex: undefined  },  {    //next color...  }];

That way, you can run sorts on this array in whatever way you'd like, and you're not trying to rip data out from markup and split it and reassign it and all that.

But really, it seems you're maybe hung up on the sort functions. Running multiple sorts one after the other will get unintended results; you have to run a single sort function that compares the next 'column' in the case the previous one is found to be equal. An RGB sort could look like:

var decimalRgbForwards = function(a,b) {  var a = a.decimalrgb,      b = b.decimalrgb;  if ( a.r === b.r ) {    if ( a.g === b.g ) {      return a.b - b.b;    } else {      return a.g - b.g;    }  } else {    return a.r - b.r;  }};

So two colors with matching r and g values would return for equality on the b value, which is just what you're looking for.

Then, you can apply the sort:

colorsData.sort(decimalRgbForwards);

..and finally iterate through that array to rebuild the markup inside the table.

Hope it helps, sir-