In English we tend to use:
- lol = laughing out loud;
- rofl = rolling on the floor laughing;
- lmao = laughing my a** off;
- roflmao = rolling on the floor laughing my a** off.
These are just some of the forms of text laughter that I first encountered on ICQ/IRC back in the 90s / early 00s. Naturally we also have 'hah', 'haha', and 'bwahahahha' :)
However, when talking to Spanish-speaking friends, aside from the regular 'jaja', I haven't found many other alternatives to express different levels of amusement. And it feels wrong to laugh sometimes when it's just something that's mildly amusing, for example.