springs - a new approach to music editing

Drag the background - select using a box
Shift+Drag the background - move around the editor
Cmd+Drag the background - create a note
Mousewheel - move around the editor
Ctrl+Mousewheel - change the display scale of the editor
Alt+Drag - copy the selected note(s) and move to a new location
Cmd+C - copy
Cmd+V - paste
Cmd+A - select all
(undo/redo coming soon)

Drag note body - move the selected note(s) in pitch and/or time
Drag right handle - change the end time of the selected note(s)
Drag left handle - change the start time of the selected note(s)
Drag left square - connect to another note by the JI interval closest to their current equal-tempered interval

Shift+Drag - adjust pitch bend of selected note(s)
Cmd+↑ - transpose up an octave
Cmd+↓ - transpose down an octave
Cmd+2 - divide the selected interval in two (or the interval between the selected notes). Also works for numbers 3 to 9
Cmd+R - reset the selected note to a pitch bend of zero

Enter - open an editing screen for adjusting the selected notes or intervals
Delete - delete the selected notes or intervals
Spacebar - start or stop playback
Shift+Spacebar - start or stop playback of only the selected notes

A W S E D F T G Y H U J K O L P ; - play back notes using the computer keyboard as a piano keyboard! the given keys correspond to chromatically ascending pitches from C to E, and they are arranged like on a piano.
Z X - shift the computer-piano keyboard up (X) or down (Z) an octave

this app is still under development. if something goes wrong, press "clear all data" and refresh the page.