If you want to validate virtually any date (formatted as YYYY/MM/DD or YYYY-MM-DD) in JavaScript with a regular expression, you can use the following (fixed on August 8, 2013):

/^(?!(?![02468][048]|[13579][26]00)..(?!(?!00)[02468][048]|[13579][26])...02.29)\d{4}([\/-])(?=0.|1[012])(?!(0[13578]|1[02]).31|02.3)\d\d\1[012]|3[01]$/

This was actually inspired by the regular expressions from this post. Of course, the best way to check a date’s validity in JavaScript is to simply use the Date() function. Here is an example function which will do either YYYY/MM/DD or MM/DD/YYYY:

function validateDate(strDate) {
  var t = /^(?=.+([\/.-])..\1)(?=.{10}$)(?:(\d{4}).|)(\d\d).(\d\d)(?:.(\d{4})|)$/;
  strDate.replace(t, function($, _, y, m, d, y2) {
    $ = new Date(y = y || y2, m, d);
    t = $.getFullYear() != y || $.getMonth() != m || $.getDate() != d;
  });
  return !t;
}

If you have used other code segments from me, you have probably realized that the above, hard-to-understand-at-a-first-glance code is normal for me. Basically, it simply reads in the year, month and day of the month into the Date() function and makes sure that the outputted date still has the same data that was sent in. Have fun! 8)


2 Comments

koloo · December 23, 2017 at 7:48 PM

Hi,
this doest work for sample 11/12/2017 , can give the expression for mm/dd/yy or mm/dd/yyyy…..thanks,

koloo · December 23, 2017 at 7:49 PM

Hi,
this doest work for sample 11/12/2017 , can you provide the expression for mm/dd/yy or mm/dd/yyyy…..thanks,

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