A simple way to remove the right comma in JS_javascript skills

Copy code The code is as follows:

function rtrim(s) {

var lastIndex = s.lastIndexOf(',');
if (lastIndex > -1) {
s = s.substring(0, lastIndex);

}
return s; A 0-based indexed integer indicating the starting position of the substring.
end
Required. A 0-based indexed integer indicating the end of the substring.

Remarks
The substring method will return a string that contains the substring from start to end (excluding end).
lastIndexOf(parameter), if the parameter does not exist, it returns -1