Problem with Regular Expression for Date

Problem with Regular Expression for Date

Since you are doing a date validation on your website, here is one way of validating the date. The script displayed below is from the article created by Ed Nutting which you can also access by visiting.

Simply visit the site to learn about the complete explanation on the script’s function and how it works. You may try the script below by simply copying and pasting it on notepad, saving it on a file, and then upload it on your website.

//Value parameter – required. All other parameters are optional.

function isDate(value, sepVal, dayIdx, monthIdx, yearIdx) {
    try {
        //Change the below values to determine which format of date you wish to check. It is set to dd/mm/yyyy by default.
        var DayIndex = dayIdx !== undefined ? dayIdx : 0;
        var MonthIndex = monthIdx !== undefined ? monthIdx : 0;
        var YearIndex = yearIdx !== undefined ? yearIdx : 0;

        value = value.replace(/-/g, "/").replace(/./g, "/");
        var SplitValue = value.split(sepVal || "/");
        var OK = true;
        if (!(SplitValue[DayIndex].length == 1 || SplitValue[DayIndex].length == 2)) {
            OK = false;
        }
        if (OK && !(SplitValue[MonthIndex].length == 1 || SplitValue[MonthIndex].length == 2)) {
            OK = false;
        }
        if (OK && SplitValue[YearIndex].length != 4) {
            OK = false;
        }
        if (OK) {
            var Day = parseInt(SplitValue[DayIndex], 10);
            var Month = parseInt(SplitValue[MonthIndex], 10);
            var Year = parseInt(SplitValue[YearIndex], 10);

            if (OK = ((Year > 1900) && (Year < new Date().getFullYear()))) {
                if (OK = (Month <= 12 && Month > 0)) {

                    var LeapYear = (((Year % 4) == 0) && ((Year % 100) != 0) || ((Year % 400) == 0));

                    if(OK = Day > 0)
                    {
                        if (Month == 2) {
                            OK = LeapYear ? Day <= 29 : Day <= 28;
                        }
                        else {
                            if ((Month == 4) || (Month == 6) || (Month == 9) || (Month == 11)) {
                                OK = Day <= 30;
                            }
                            else {
                                OK = Day <= 31;
                            }
                        }
                    }
                }
            }
        }
        return OK;
    }
    catch (e) {
        return false;
    }
}