jquery method to delete the last character of a string parsing_jquery

String: var s = "1,2,3,4,5,"

Goal: Delete the last ","

Method:
s=s.substring(0,s.Length-1);

String: var s2 = "img/upload/123.jpg"

Goal: Get the file name (excluding suffix)

Method:
s2=s2.substring(s2.lastIndexOf('/') 1, s2.lastIndexOf('.'));