How can I use regex to get all the characters after a specific character, e.g. comma (",")

Need a Regex to get all characters after , (not including it) from a variable. This variable can contain for example

'SELECT___100E___7',24
'SELECT___100E___7',1
'SELECT___100E___7',286
'SELECT___100E___7',5147

Note: There can be any length of characters after the , in this variable.

An explanation of the regexp would be a added help for the novice :)

Edit: a javascript answer would be just as good