javascript regexp for numbers between 00-59 (seconds)

Question

I want to check if a field is a valid time value (just seconds). So I want to accept the numbers from 0 to 59. I came out with this:

[0-5][0-9]?

Answer 1

In your 2nd regex, you need to remove that ? from the first part, and make it [1-5] instead of [0-5]:

[0-9]|[1-5][0-9]

And if you want to be flexible enough to allow both 7 and 07, then use [0-5]:

[0-9]|[0-5][0-9]  

And then, simplifying the above regex, you can use:

[0-5]?[0-9]   // ? makes [0-5] part optional