isValidDate

dd.MM.yyyy

JavaScript

// Validates that the input string is a valid date formatted as "dd.MM.yyyy"
function isValidDate(dateString)
{
    // First check for the pattern
    if(!/^\d{2}\.\d{2}\.\d{4}$/.test(dateString))
        return false;

    // Parse the date parts to integers
    var parts = dateString.split(".");
    var day = parseInt(parts[0], 10);
    var month = parseInt(parts[1], 10);
    var year = parseInt(parts[2], 10);

    // Check the ranges of month and year
    if(year < 1000 || year > 3000 || month == 0 || month > 12)
        return false;

    var monthLength = [ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ];

    // Adjust for leap years
    if(year % 400 == 0 || (year % 100 != 0 && year % 4 == 0))
        monthLength[1] = 29;

    // Check the range of the day
    return day > 0 && day <= monthLength[month - 1];
};

var l = function(msg) { console.log(msg); };

l("28.02.2014");
l(isValidDate("00.02.2014"));

l("29.02.2014");
l(isValidDate("29.02.2014"));