valid date in format yyyy-mm-dd using regex code example

Example 1: regex for date mm/dd/yyyy

function validateDate(testdate) {
    var date_regex = /^\d{2}\/\d{2}\/\d{4}$/ ;
    return date_regex.test(testdate);
}

Example 2: regex for yyyy-mm-dd

^\d{4}\-(0?[1-9]|1[012])\-(0?[1-9]|[12][0-9]|3[01])$