Use map() and parseInt()

var res = ['2', '10', '11'].map(function(v) {
  return parseInt(v, 10);
});

document.write('<pre>' + JSON.stringify(res, null, 3) + '<pre>')

More simplified ES6 arrow function

var res = ['2', '10', '11'].map(v => parseInt(v, 10));

document.write('<pre>' + JSON.stringify(res, null, 3) + '<pre>')

Or using Number

var res = ['2', '10', '11'].map(Number);

document.write('<pre>' + JSON.stringify(res, null, 3) + '<pre>')

var res = ['2', '10', '11'].map(v => +v );

document.write('<pre>' + JSON.stringify(res, null, 3) + '<pre>')

Also there is some other method which is present in it's documentation please look at Polyfill , thanks to @RayonDabre for pointing out.

You can use Array.map to convert each element into a number.

var a = "1,2,3,4";

var b = a.split(',').map(function(item) {
    return parseInt(item, 10);
});

Check the Docs

Or more elegantly as pointed out by User: thg435

var b = a.split(',').map(Number);

Where Number() would do the rest:check here

Note: For older browsers that don't support map, you can add an implementation yourself like:

Array.prototype.map = Array.prototype.map || function(_x) {
    for(var o=[], i=0; i<this.length; i++) { 
        o[i] = _x(this[i]); 
    }
    return o;
};

Alternatively, you can one-line it using .map().

var arr = ["34", "23", "21"];
arr.map(Number);
>>> [34, 23, 21]

ECMAScript5 provides a map method for Arrays, applying a function to all elements of an array. Here is an example:

var a = ['1','2','3']
var result = a.map(function (x) { 
  return parseInt(x, 10); 
});

console.log(result);

See Array.prototype.map()

A quick one for modern browsers:

'14 2'.split(' ').map(Number);

// [14, 2]`

If the string = [1,1], then you can simply parse it as json. Like this:

const str = '[1,1]';
const resultArr = JSON.parse(str);

console.log(resultArr);

The result is an array of integers:

Array:
0: 1
1: 1