Regular expression for a list of items separated by comma or by comma and a space

Question

Hey, I can\'t figure out how to write a regular expression for my website, I would like to let the user input a list of items (tags) separated by comma or by comma and a spa

Answer 1

I often work with coma separated pattern, and for me, this works :

((^|[,])pattern)+

where "pattern" is the single element regexp