How do I validate a date in this format (yyyy-mm-dd) using jquery?

Question

I am attempting to validate a date in this format: (yyyy-mm-dd). I found this solution but it is in the wrong format for what I need, as in: (mm/dd/yyyy).

Here is the link to that solution: http://jsfiddle.net/ravi1989/EywSP/848/

My code is below:

function isDate(txtDate) {     var currVal = txtDate;     if(currVal == '')         return false;      var rxDatePattern = /^(\d{1,2})(\/|-)(\d{1,2})(\/|-)(\d{4})$/; //Declare Regex     var dtArray = currVal.match(rxDatePattern); // is format OK?      if (dtArray == null)          return false;      //Checks for mm/dd/yyyy format.     dtMonth = dtArray[1];     dtDay= dtArray[3];     dtYear = dtArray[5];              if (dtMonth < 1 || dtMonth > 12)          return false;     else if (dtDay < 1 || dtDay> 31)          return false;     else if ((dtMonth==4 || dtMonth==6 || dtMonth==9 || dtMonth==11) && dtDay ==31)          return false;     else if (dtMonth == 2)      {         var isleap = (dtYear % 4 == 0 && (dtYear % 100 != 0 || dtYear % 400 == 0));         if (dtDay> 29 || (dtDay ==29 && !isleap))                  return false;     }     return true; } 

What regex pattern can I use for this that will account for invalid dates and leap years?

Answer 1

I expanded just slightly on the isValidDate function Thorbin posted above (using a regex). We use a regex to check the format (to prevent us from getting another format which would be valid for Date). After this loose check we then actually run it through the Date constructor and return true or false if it is valid within this format. If it is not a valid date we will get false from this function.

function isValidDate(dateString) {    var regEx = /^\d{4}-\d{2}-\d{2}$/;    if(!dateString.match(regEx)) return false;  // Invalid format    var d = new Date(dateString);    var dNum = d.getTime();    if(!dNum && dNum !== 0) return false; // NaN value, Invalid date    return d.toISOString().slice(0,10) === dateString;  }      /* Example Uses */  console.log(isValidDate("0000-00-00"));  // false  console.log(isValidDate("2015-01-40"));  // false  console.log(isValidDate("2016-11-25"));  // true  console.log(isValidDate("1970-01-01"));  // true = epoch  console.log(isValidDate("2016-02-29"));  // true = leap day  console.log(isValidDate("2013-02-29"));  // false = not leap day