Date Format Validation in Javascript

 

There’re several different ways to handle Date values through the script, all depends on the exact need. In some cases, there’s a need to enter a date value manually, as text, yet to force it to be in a specific valid date format.

Below is the javascript code to valdate date with given format. Add this code inside the script tag

function ValidateDate(dt, format) {

    var isValid = true;

    if(dt.length != format.length) {
        isValid = false;
    }

    format = format.replace(/\ /g, "/").toLowerCase();
    dt = dt.replace(/\ /g, "/");
    var dateFormat = dt;
    //Get Day Value
    var day = 0;
    if(format.indexOf("dd") > -1) {
        var index = format.indexOf("dd"),
        day = dt.substring(index * 1 + 2);
      dateFormat=  dateFormat.replaceAt(index, "dd");

    } else if(format.indexOf("d") > -1) {
        var index = format.indexOf("dd"),
        day = dt.substring(inde, index * 1 + 1);
       dateFormat=  dateFormat.replaceAt(index, "d");
    } else {
        isValid = false;
    }

    //Get Month Value
    var month = 0;
    if(format.indexOf("mmm") > -1) {
        var index = format.indexOf("mmm"),
        month = dt.substring(index, index * 1 + 3);
      dateFormat=   dateFormat.replaceAt(index, "mmm");
    } else if(format.indexOf("mm") > -1) {
        var index = format.indexOf("mm"),
        month = dt.substring(index, index * 1 + 2);
       dateFormat=  dateFormat.replaceAt(index, "mm");
    }
    else {
        isValid = false;
    }

    var year = 0;
    if(format.indexOf("yyyy") > -1) {
        var index = format.indexOf("yyyy"),
        year = dt.substring(index, index * 1 + 4);
       dateFormat=  dateFormat.replaceAt(index, "yyyy");
    } else if(format.indexOf("yy") > -1) {
        var index = format.indexOf("yy"),
        year = dt.substring(index, index * 1 + 2);
      dateFormat=   dateFormat.replaceAt(index, "yy");
    }
    else {
        isValid = false;
    }

    if(dateFormat != format)
    {
        isValid = false;
    }

    console.log(day);
    console.log(month);
    console.log(year);
	console.log(isValid);

}
String.prototype.replaceAt = function(index, replacement) {
    return this.substr(0, index) + replacement + this.substr(index + replacement.length);
}

ValidateDate("12-07-2017", "MM-DD-YYYY");
ValidateDate("12-07-2017", "DD/MM/YYYY");
ValidateDate("2017-07-12", "YYYY-MM-DD");