Javascript - Regex to validate date format [duplicate]

Answer 1

Don't re-invent the wheel. Use a pre-built solution for parsing dates, like http://www.datejs.com/

Answer 2

If you want to validate your date(YYYY-MM-DD) along with the comparison it will be use full for you...

    function validateDate()
    {
     var newDate = new Date();
     var presentDate = newDate.getDate();
     var presentMonth = newDate.getMonth();
     var presentYear = newDate.getFullYear();
     var dateOfBirthVal = document.forms[0].dateOfBirth.value;
    if (dateOfBirthVal == null) 
    return false;
    var validatePattern = /^(\d{4})(\/|-)(\d{1,2})(\/|-)(\d{1,2})$/;
    dateValues = dateOfBirthVal.match(validatePattern);
    if (dateValues == null) 
    {
        alert("Date of birth should be null and it should in the format of yyyy-mm-dd")
    return false;
        }
    var birthYear = dateValues[1];        
    birthMonth = dateValues[3];
    birthDate=  dateValues[5];
    if ((birthMonth < 1) || (birthMonth > 12)) 
    {
        alert("Invalid date")
    return false;
        }
    else if ((birthDate < 1) || (birthDate> 31)) 
    {
        alert("Invalid date")
    return false;
        }
    else if ((birthMonth==4 || birthMonth==6 || birthMonth==9 || birthMonth==11) && birthDate ==31) 
    {
        alert("Invalid date")
    return false;
        }
    else if (birthMonth == 2){ 
    var isleap = (birthYear % 4 == 0 && (birthYear % 100 != 0 || birthYear % 400 == 0));
    if (birthDate> 29 || (birthDate ==29 && !isleap)) 
    {
        alert("Invalid date")
    return false;
        }
    }
    else if((birthYear>presentYear)||(birthYear+70<presentYear))
        {
        alert("Invalid date")
        return false;
        }
    else if(birthYear==presentYear)
        {
        if(birthMonth>presentMonth+1)
            {
            alert("Invalid date")
            return false;
            }
        else if(birthMonth==presentMonth+1)
            {
            if(birthDate>presentDate)
                {
                alert("Invalid date")
                return false;
                }
            }
        }
return true;
    }

Answer 3

Make use of brackets /^\d{2}[.-/]\d{2}[.-/]\d{4}$/ http://download.oracle.com/javase/tutorial/essential/regex/char_classes.html

Answer 4

Format, days, months and year:

var regex = /^(0[1-9]|[12][0-9]|3[01])[- /.](0[1-9]|1[012])[- /.](19|20)\d\d$/;

Answer 5

To make sure it will work, you need to validate it.

function mmIsDate(str) {

    if (str == undefined) { return false; }

    var parms = str.split(/[\.\-\/]/);

    var yyyy = parseInt(parms[2], 10);

    if (yyyy < 1900) { return false; }

    var mm = parseInt(parms[1], 10);
    if (mm < 1 || mm > 12) { return false; }

    var dd = parseInt(parms[0], 10);
    if (dd < 1 || dd > 31) { return false; }

    var dateCheck = new Date(yyyy, mm - 1, dd);
    return (dateCheck.getDate() === dd && (dateCheck.getMonth() === mm - 1) && dateCheck.getFullYear() === yyyy);

};

Answer 6

You can use regular multiple expressions with the use of OR (|) operator.

function validateDate(date){
    var regex=new RegExp("([0-9]{4}[-](0[1-9]|1[0-2])[-]([0-2]{1}[0-9]{1}|3[0-1]{1})|([0-2]{1}[0-9]{1}|3[0-1]{1})[-](0[1-9]|1[0-2])[-][0-9]{4})");
    var dateOk=regex.test(date);
    if(dateOk){
        alert("Ok");
    }else{
        alert("not Ok");
    }
}

Above function can validate YYYY-MM-DD, DD-MM-YYYY date formats. You can simply extend the regular expression to validate any date format. Assume you want to validate YYYY/MM/DD, just replace "[-]" with "[-|/]". This expression can validate dates to 31, months to 12. But leap years and months ends with 30 days are not validated.