Man, those things are still around? When I first got into the hobby we were all looking at them and wishing they were easier to use... IIRC they don't do any of the work for you, so making a driver for them to get Espruino to support it would be kind of a nightmare.
These days everyone just uses ESP8266's for LAN connectivity. I'll bet someone (not me, I have WAY too much on my plate) could take a blue-pill-like board, or an Arduino (I think there's an Arduino library for it? Might not even be that hard, if there's already a decent library to put a wrapper around... have it talk to whatever over serial, and rip off the ESP8266 AT-firmware API... The hardware would be cheap - on the other hand, they'd be competing with $2 ESP8266s, so it might be hard to get people's attention. Wires seem to be kind of passe now... I used to be a "screw wifi, give me a CAT-5 cable" type, but... I haven't plugged into the network cable since I think before the quarantimes... wifi has finally gotten good enough, and they've got the volume such that they're cheaper than dirt...
A better choice are WizNet devices, because the driver is available for Espruino devices.
Preferred is the 5500 chip.
I'd always intended to try something with ENC28J60 but as @DrAzzy says it's a nightmare. Basically they only send/receive packets - so while you could probably handle UDP (at 10Mbits/sec) semi-easily to do TCP/IP you'd have to have your own TCP/IP stack built into Espruino.
Definitely worth looking at the WIZ5500 though - there are some lovely little boards, for example:
Costs around £5, is 100mbps, and should work great with Espruino.
Can confirm, that those work great with Espruino.
Oh dang, nice, the mass production chinese electronic crap vendors got into the game! They were a hell of a lot more when I was working with them...
Hello - does anyone tried to communicate with ethernet via this?