String to Date

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
<div id="date1"></div>
<br>
<div id="date2"></div>
<br>
<div id="date3"></div>
<br>
<div id="date4"></div>
<br>
<div id="date5"></div>
<br>
<div id="date6"></div>
<br>
<div id="date7"></div>
<br>
<div id="date8"></div>
<br>
<div id="date9"></div>
<br>
<div id="date10"></div>
<br>
<div id="date11"></div>
<br>
<div id="date12"></div>
<br>
<div id="date13"></div>
<br>

JavaScript

String.prototype.toDate = function(format, delimiter) {
    var date = this;
    var formatedDate = null;
    var formatLowerCase = format.toLowerCase();
    var formatItems = formatLowerCase.split(delimiter);
    var dateItems = date.split(delimiter);
    var monthIndex = formatItems.indexOf("mm");
    var monthNameIndex = formatItems.indexOf("mmm");
    var dayIndex = formatItems.indexOf("dd");
    var yearIndex = formatItems.indexOf("yyyy");
    var d = dateItems[dayIndex];
    if (d < 10) {
    	d = "0"+ d;
    }
    if (monthIndex > -1) {
        var month = parseInt(dateItems[monthIndex]);
        month -= 1;
        if (month < 10) {
            month = "0" + month;
        }
        formatedDate = new Date(dateItems[yearIndex], month, d);
    } else if (monthNameIndex > -1) {
        var monthName = dateItems[monthNameIndex];
        month = getMonthIndex(monthName);
        if (month < 10) {
            month = "0" + month;
        }
        formatedDate = new Date(dateItems[yearIndex], month, d);
    }
    return formatedDate;
};

function getMonthIndex(name) {
    name = name.toLowerCase();
    if (name == "jan" || name == "january") {
        return 0;
    } else if (name == "feb" || name == "february") {
        return 1;
    } else if (name == "mar" || name == "march") {
        return 2;
    } else if (name == "apr" || name == "april") {
        return 3;
    } else if (name == "may" || name == "may") {
        return 4;
    } else if (name == "jun" || name == "june") {
        return 5;
    } else if (name == "jul" || name == "july") {
        return 6;
    } else if (name == "aug" || name == "august") {
        return 7;
    } else if (name == "sep" || name == "september") {
        return 8;
    } else if (name == "oct" || name == "october") {
        return 9;
    } else if (name == "nov" || name == "november") {
        return 10;
    } else if (name == "dec" || name == "december") {
        return 11;
   ...