Edit in JSFiddle

(function () {

    var DateParseString = Date.parse("2014/01/01");
    var _DateParseString = document.getElementById("DateParseString");
    _DateParseString.innerHTML = DateParseString;
    console.log(DateParseString);

    var DateParseNull = Date.parse(null);
    var _DateParseNull = document.getElementById("DateParseNull");
    _DateParseNull.innerHTML = DateParseNull;
    console.log(DateParseNull);
    
    var DateParseUndefined = Date.parse(null);
    var _DateParseUndefined = document.getElementById("DateParseUndefined");
    _DateParseUndefined.innerHTML = DateParseUndefined;
    console.log(DateParseUndefined);
    
    
})();

<div id="DateParseString"></div>
<div id="DateParseNull"></div>
<div id="DateParseUndefined"></div>