Echidna Wars DX is a paid game, purchases of which support the original developers (which I encourage). I don't believe any ports to an HTML format exist for it? And I would highly recommend anyone wanting that, or wanting to MAKE that, to simply direct their attention to the official source of Echidna Wars DX.
If Asimofu and D-Gate go defunct and it becomes impossible to acquire legitimately from the dlsite, then I would consider it free game (pun not intended) and no longer piracy. Until then, though, please support the original creators by buying and playing their game!