A clean way to do it would be to convert each date to a Date() and take the max

ES6:

new Date(Math.max(...a.map(e => new Date(e.MeasureDate))));

JS:

new Date(Math.max.apply(null, a.map(function(e) {
  return new Date(e.MeasureDate);
})));

where a is the array of objects.

What this does is map each of the objects in the array to a date created with the value of MeasureDate. This mapped array is then applied to the Math.max function to get the latest date and the result is converted to a date.

By mapping the string dates to JS Date objects, you end up using a solution like Min/Max of dates in an array?

--

A less clean solution would be to simply map the objects to the value of MeasureDate and sort the array of strings. This only works because of the particular date format you are using.

a.map(function(e) { return e.MeasureDate; }).sort().reverse()[0]

If performance is a concern, you may want to reduce the array to get the maximum instead of using sort and reverse.

Code is tested with IE,FF,Chrome and works properly:

var dates=[];
dates.push(new Date("2011/06/25"))
dates.push(new Date("2011/06/26"))
dates.push(new Date("2011/06/27"))
dates.push(new Date("2011/06/28"))
var maxDate=new Date(Math.max.apply(null,dates));
var minDate=new Date(Math.min.apply(null,dates));

var array = [{"source":"2016-11-02","sourcecount":38},{"source":"2016-11-01","sourcecount":30},{"source":"2016-11-02","sourcecount":30},{"source":"2016-11-03","sourcecount":30}];

var max = null;
var min = null;

for (var i = 0; i < array.length; i++) {
  var current = array[i];
  if (max === null || current.source > max.source) {
    max = current;
  }
  if (min === null || current.source < min.source) {
    min = current;
  }
}

document.getElementById('maxResult').innerHTML = max.source;
document.getElementById('minResult').innerHTML = min.source;

Max: <span id="maxResult"></span><br/ >
Min: <span id="minResult"></span>

1) Use map to extract the dates:

var dates = data.map(function(x) { return new Date(x[4]); })

2) Use Math.max / Math.min to get the highest / lowest dates:

var latest = new Date(Math.max.apply(null,dates));
var earliest = new Date(Math.min.apply(null,dates));

There is my solution, this is a bit long, but very easy to understand and edit for any update. I'm sure we can solve it with 4-5 lines, but whatever, it works.

First, define a month array :

var month = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];

Like every time you need to search min/max in an array, you need to initialize min and max with the first value :

var max_end_date = data[0].Events[1].Date;
var min_start_date = data[0].Events[0].Date;

And then, split every date for compare year / month for start en end, and you have a result like this :

$.each(data, function(k, v) {
    var month_min_start_date = min_start_date.split("-")[0];
    var year_min_start_date = min_start_date.split("-")[1];

    var current_start_date = v.Events[0].Date;
    var month_current_start_date = current_start_date.split("-")[0];
    var year_current_start_date = current_start_date.split("-")[1];

    if (year_current_start_date < year_min_start_date 
        || year_current_start_date == year_min_start_date && month.indexOf(month_current_start_date) < month.indexOf(month_min_start_date)) {
            min_start_date = current_start_date;
        }

    var month_max_end_date = max_end_date.split("-")[0];
    var year_max_end_date = max_end_date.split("-")[1];

    var current_end_date = v.Events[1].Date;
    var month_current_end_date = current_end_date.split("-")[0];
    var year_current_end_date = current_end_date.split("-")[1];

    if (year_current_end_date > year_max_end_date 
        || year_current_end_date == year_max_end_date && month.indexOf(month_current_end_date) > month.indexOf(month_max_end_date)) {
            max_end_date = current_end_date;
        }

})

You can try it on JSFiddle

Try wrapping document.getElementById('date1').value in new Date().getTime() .

Also input type="date" accepts value as yyyy-mm-dd ; try using .toJSON() , String.prototype.slice() to set date properly for #maxdate as yyyy-mm-dd from value returned as maxDate

function checkMaxDate() {
  var dateArray = [];
  var date1 = dateArray.push(new Date(document.getElementById('date1').value).getTime());
  var date2 = dateArray.push(new Date(document.getElementById('date2').value).getTime());
  var maxDate = Math.max.apply(Math, dateArray);
  document.getElementById('maxdate').value = new Date(maxDate).toJSON().slice(0, 10);
}

Date 1:
<input type="date" id="date1" />Date 2:
<input type="date" id="date2" />Max Date:
<input type="date" id="maxdate" />
<button type="button" onclick="checkMaxDate()">Check</button>

Use Array#sort with custom sort function and get the last(max) and first(min) values.

data = ["2016/10/13 00:00:00", "2016/10/13 00:30:00", "2016/10/13 01:00:00", "2016/10/13 01:30:00", "2016/10/13 02:00:00", "2016/10/13 02:30:00", "2016/10/13 03:00:00", "2016/10/13 03:30:00", "2016/10/13 04:00:00", "2016/10/13 04:30:00"];

var sorted = data.slice() // copy the array for keeping original array with order
  // sort by parsing them to date
  .sort(function(a, b) {
    return new Date(a) - new Date(b);
  });

// get the first and last values
console.log(
  'max :', sorted.pop(), 'min :', sorted.shift()
);

Or with a simple Array#forEach loop.

data = ["2016/10/13 00:00:00", "2016/10/13 00:30:00", "2016/10/13 01:00:00", "2016/10/13 01:30:00", "2016/10/13 02:00:00", "2016/10/13 02:30:00", "2016/10/13 03:00:00", "2016/10/13 03:30:00", "2016/10/13 04:00:00", "2016/10/13 04:30:00"];

// initially set max and min as first element
var max = data[0],
  min = data[0];

// iterate over array values and update min & max
data.forEach(function(v) {
  max = new Date(v) > new Date(max)? v: max;
  min = new Date(v) < new Date(min)? v: min;
});

console.log('max :', max, 'min :', min);