I am new to regular expressions. I have a text field and I need to limit the input to numbers and one comma. I know how to limit to numbers. But I have another condition. If the user enters a comma, they must enter another number after that. There is no restriction on the number of digits. There can only be one comma. The following are all valid inputs: 123456 4567,8907
but I can't allow 4567,. I have this pattern, pattern="[0-9]+([,][0-9]+)?" but it's not working.
