Guitoro, a free browser-based virtual guitar, lets users play with a keyboard or touch screen

Guitoro is a free virtual guitar that runs in a web browser. You can play it with your computer keyboard, a mouse, or your fingers on a phone or tablet.

On a computer keyboard, your left hand holds chords on the letter keys and your right hand strums with H and J. There are 15 chords under your fingers, plus keys for arpeggios (notes of a chord played one at a time), single strings, chucks and palm mutes. On a touch screen, you tap a chord pad and swipe the strings, with up to five fingers at once.

With a mouse, you drag across the strings. A fast swipe plays louder, a slow drag rolls the notes one by one, and a click plucks a single string. On a computer, a mode called Solo turns each keyboard row into a string and each column into a fret, with bends and vibrato on the arrow keys.

You can choose a steel-string acoustic, a classic guitar, an electric guitar or a four-string bass. According to the site, every guitar and bass note is a recording of a real instrument. There is nothing to download and no account to create. It offers six strings, 15 chords in every key and 51 songs to play along with.

The main teaching idea is slowing songs down. Each song plays its best-known part close to the original recording, stroke for stroke. You can slow it to 20% of full speed, and the chords, the strum and the band slow down together.

While a song plays, each string lights up when it is hit, so you can see whether a stroke hits all six strings, only the bass strings or just the top three. A pick swings down and up with the strumming pattern. The neck shows finger numbers from 1 to 4, barres, muted strings and the capo.

Then you try it yourself. If you have no guitar, you can play the song's chords on the keys or the screen. The next chord lights green, and the song waits until you play it. There is no score. If you do have a guitar, a My guitar mode on computers shows the strum or picking pattern, a chord strip and the speed, so you can play along and raise the tempo as you improve.

Getting started is simple. Pick an instrument, then a chord. The default key is G major, and the middle row of keys, A S D F G, holds G, C, D, Em and Am. Auto strum is on by default, so the chord strums itself. Turn it off to strum with H (down) and J (up).

Other features include strum and picking patterns, a switchable backing band with drums, bass line and strings, and a recorder. Your recorded takes are saved in a Recordings section.