Code

Quick date validation with a Regular Expression

/(?:19|20)[0-9]{2}-(?:(?:0[1-9]|1[0-2])-(?:0[1-9]|1[0-9]|2[0-8])|(?:(?!02)(?:0[1-9]|1[0-2])-(?:29|30))|(?:(?:0[13578]|1[02])-31))/

Here's the breakdown of what it does:

Given a date format of YYYY-MM-DD (standard MySQL date format and easiest format for sorting) it makes sure that

  1. the year is numeric and starts with 20 or 19, and
  2. the month is numeric and is either
    1. between 01 - 12 and followed by a numeric day value between 01-28;
    2. between 01 - 12 but not 02 and followed by a day value of 29 or 30; or
    3. one of 01,03,05,07,08,10,12 and followed by a day value of 31

I have left out Feb. 29th so that you are forced to do a secondary leap year check.

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2010.01.28 11:43 AM | Permalink 0 Comments