Unfortunately I found out that

var mydate = new Date('2014-04-03');
console.log(mydate.toDateString());

returns "Wed Apr 02 2014". I know it sounds crazy, but it happens for some users.

The bulletproof solution is the following:

var parts ='2014-04-03'.split('-');
// Please pay attention to the month (parts[1]); JavaScript counts months from 0:
// January - 0, February - 1, etc.
var mydate = new Date(parts[0], parts[1] - 1, parts[2]); 
console.log(mydate.toDateString());

var st = "26.04.2013";
var pattern = /(\d{2})\.(\d{2})\.(\d{4})/;
var dt = new Date(st.replace(pattern,'$3-$2-$1'));

And the output will be:

dt => Date {Fri Apr 26 2013}

function stringToDate(_date,_format,_delimiter)
{
            var formatLowerCase=_format.toLowerCase();
            var formatItems=formatLowerCase.split(_delimiter);
            var dateItems=_date.split(_delimiter);
            var monthIndex=formatItems.indexOf("mm");
            var dayIndex=formatItems.indexOf("dd");
            var yearIndex=formatItems.indexOf("yyyy");
            var month=parseInt(dateItems[monthIndex]);
            month-=1;
            var formatedDate = new Date(dateItems[yearIndex],month,dateItems[dayIndex]);
            return formatedDate;
}

stringToDate("17/9/2014","dd/MM/yyyy","/");
stringToDate("9/17/2014","mm/dd/yyyy","/")
stringToDate("9-17-2014","mm-dd-yyyy","-")

Recommendation: I recommend to use a package for dates that contains a lot of formats because the timezone and format time management is really a big problem, moment js solve a lot of formats. You could parse easily date from a simple string to date but I think that is a hard work to support all formats and variations of dates.

Update: Moment is now deprecated, A good alternative for moment is datefns

moment.js () is a complete and good package for use dates and supports ISO 8601 strings.

You could add a string date and format.

moment("12-25-1995", "MM-DD-YYYY");

And you could check if a date is valid.

moment("not a real date").isValid(); //Returns false

Some display examples

let dt = moment("02-01-2019", "MM-DD-YYYY");
console.log(dt.fromNow()+' |'+dt.format('LL')) 
// output: "3 months ago | February 1, 2019"

See documentation

Pass it as an argument to Date():

var st = "date in some format"
var dt = new Date(st);

You can access the date, month, year using, for example: dt.getMonth().

If you can use the terrific luxon library you can easily parse your date using e.g.

var luxonDate = DateTime.fromISO("2014-09-15T09:00:00");

and can access the JS date object via

luxonDate().toJSDate();

The old answer used MomentJS

var momentDate = moment("2014-09-15 09:00:00");
momentDate ().toDate();

For those who are looking for a tiny and smart solution:

String.prototype.toDate = function(format)
{
  var normalized      = this.replace(/[^a-zA-Z0-9]/g, '-');
  var normalizedFormat= format.toLowerCase().replace(/[^a-zA-Z0-9]/g, '-');
  var formatItems     = normalizedFormat.split('-');
  var dateItems       = normalized.split('-');

  var monthIndex  = formatItems.indexOf("mm");
  var dayIndex    = formatItems.indexOf("dd");
  var yearIndex   = formatItems.indexOf("yyyy");
  var hourIndex     = formatItems.indexOf("hh");
  var minutesIndex  = formatItems.indexOf("ii");
  var secondsIndex  = formatItems.indexOf("ss");

  var today = new Date();

  var year  = yearIndex>-1  ? dateItems[yearIndex]    : today.getFullYear();
  var month = monthIndex>-1 ? dateItems[monthIndex]-1 : today.getMonth()-1;
  var day   = dayIndex>-1   ? dateItems[dayIndex]     : today.getDate();

  var hour    = hourIndex>-1      ? dateItems[hourIndex]    : today.getHours();
  var minute  = minutesIndex>-1   ? dateItems[minutesIndex] : today.getMinutes();
  var second  = secondsIndex>-1   ? dateItems[secondsIndex] : today.getSeconds();

  return new Date(year,month,day,hour,minute,second);
};

Example:

"22/03/2016 14:03:01".toDate("dd/mm/yyyy hh:ii:ss");
"2016-03-29 18:30:00".toDate("yyyy-mm-dd hh:ii:ss");

Just new Date(st);

Assuming that it's the proper format.

new Date(2000, 10, 1) will give you "Wed Nov 01 2000 00:00:00 GMT+0100 (CET)"

See that 0 for month gives you January

If you want to convert from the format "dd/MM/yyyy". Here is an example:

var pattern = /^(\d{1,2})\/(\d{1,2})\/(\d{4})$/;
var arrayDate = stringDate.match(pattern);
var dt = new Date(arrayDate[3], arrayDate[2] - 1, arrayDate[1]);

This solution works in IE versions less than 9.

Timestamps should be casted to a Number

var ts = '1471793029764';
ts = Number(ts); // cast it to a Number
var date = new Date(ts); // works

var invalidDate = new Date('1471793029764'); // does not work. Invalid Date

Date.parse almost gets you what you want. It chokes on the am/pm part, but with some hacking you can get it to work:

var str = 'Sun Apr 25, 2010 3:30pm',
    timestamp;

timestamp = Date.parse(str.replace(/[ap]m$/i, ''));

if(str.match(/pm$/i) >= 0) {
    timestamp += 12 * 60 * 60 * 1000;
}

Performance

Today (2020.05.08) I perform tests for chosen solutions - for two cases: input date is ISO8601 string (Ad,Bd,Cd,Dd,Ed) and input date is timestamp (At, Ct, Dt). Solutions Bd,Cd,Ct not return js Date object as results, but I add them because they can be useful but I not compare them with valid solutions. This results can be useful for massive date parsing.

Conclusions

• Solution new Date (Ad) is 50-100x faster than moment.js (Dd) for all browsers for ISO date and timestamp
• Solution new Date (Ad) is ~10x faster than parseDate (Ed)
• Solution Date.parse(Bd) is fastest if wee need to get timestamp from ISO date on all browsers