You simply make each item within the array an array.

var x = new Array(10);



for (var i = 0; i < x.length; i++) {

  x[i] = new Array(3);

}



console.log(x);

Similar to activa's answer, here's a function to create an n-dimensional array:

function createArray(length) {

    var arr = new Array(length || 0),

        i = length;



    if (arguments.length > 1) {

        var args = Array.prototype.slice.call(arguments, 1);

        while(i--) arr[length-1 - i] = createArray.apply(this, args);

    }



    return arr;

}



createArray();     //  or new Array()



createArray(2);    // new Array(2)



createArray(3, 2); // [new Array(2),

                   //  new Array(2),

                   //  new Array(2)]

Javascript only has 1-dimensional arrays, but you can build arrays of arrays, as others pointed out.

The following function can be used to construct a 2-d array of fixed dimensions:

function Create2DArray(rows) {

  var arr = ;



  for (var i=0;i<rows;i++) {

     arr[i] = ;

  }



  return arr;

}

The number of columns is not really important, because it is not required to specify the size of an array before using it.

Then you can just call:

var arr = Create2DArray(100);



arr[50][2] = 5;

arr[70][5] = 7454;

// ...

The easiest way:

var myArray = [];

The reason some say that it isn't possible is because a two dimensional array is really just an array of arrays. The other comments here provide perfectly valid methods of creating two dimensional arrays in JavaScript, but the purest point of view would be that you have a one dimensional array of objects, each of those objects would be a one dimensional array consisting of two elements.

So, that's the cause of the conflicting view points.

Few people show the use of push:

To bring something new, I will show you how to initialize the matrix with some value, example: 0 or an empty string "".

Reminding that if you have a 10 elements array, in javascript the last index will be 9!

function matrix( rows, cols, defaultValue){



  var arr = ;



  // Creates all lines:

  for(var i=0; i < rows; i++){



      // Creates an empty line

      arr.push();



      // Adds cols to the empty line:

      arr[i].push( new Array(cols));



      for(var j=0; j < cols; j++){

        // Initializes:

        arr[i][j] = defaultValue;

      }

  }



return arr;

}

usage examples:

x = matrix( 2 , 3,''); // 2 lines, 3 cols filled with empty string

y = matrix( 10, 5, 0);// 10 lines, 5 cols filled with 0

Two-liner:

var a = ; 

while(a.push() < 10);

It will generate an array a of the length 10, filled with arrays.
(Push adds an element to an array and returns the new length)

The sanest answer seems to be

var nrows = ~~(Math.random() * 10);

var ncols = ~~(Math.random() * 10);

console.log(`rows:${nrows}`);

console.log(`cols:${ncols}`);

var matrix = new Array(nrows).fill(0).map(row => new Array(ncols).fill(0));

console.log(matrix);

Note we can't directly fill with the rows since fill uses shallow copy constructor, therefore all rows would share the same memory...here is example which demonstrates how each row would be shared (taken from other answers):

// DON'T do this: each row in arr, is shared

var arr = Array(2).fill(Array(4));

arr[0][0] = 'foo'; // also modifies arr[1][0]

console.info(arr);

How to create an empty two dimensional array (one-line)

Array.from(Array(2), () => new Array(4))

2 and 4 being first and second dimensions respectively.

We are making use of Array.from, which can take an array-like param and an optional mapping for each of the elements.

Array.from(arrayLike[, mapFn[, thisArg]])

var arr = Array.from(Array(2), () => new Array(4));

arr[0][0] = 'foo';

console.info(arr);

The same trick can be used to Create a JavaScript array containing 1...N

Alternatively (but more inefficient 12% with n = 10,000)

Array(2).fill(null).map(() => Array(4))

The performance decrease comes with the fact that we have to have the first dimension values initialized to run .map. Remember that Array will not allocate the positions until you order it to through .fill or direct value assignment.

var arr = Array(2).fill(null).map(() => Array(4));

arr[0][0] = 'foo';

console.info(arr);

Follow up

Why doesn't this work?

 Array(2).fill(Array(4));

While it does return the apparently desired two dimensional array ([ [ <4 empty items> ], [ <4 empty items> ] ]), there a catch: first dimension arrays have been copied by reference. That means a arr[0][0] = 'foo' would actually change two rows instead of one.

var arr = Array(2).fill(Array(4));

arr[0][0] = 'foo';

console.info(arr);

console.info(arr[0][0], arr[1][0]);

The easiest way:

var arr  = ;



var arr1 = ['00','01'];

var arr2 = ['10','11'];

var arr3 = ['20','21'];



arr.push(arr1);

arr.push(arr2);

arr.push(arr3);



alert(arr[0][1]); // '01'

alert(arr[1][1]); // '11'

alert(arr[2][0]); // '20'

This is what i achieved :

var appVar = [];

appVar[0][4] = "bineesh";

appVar[0][5] = "kumar";

console.log(appVar[0][4] + appVar[0][5]);

console.log(appVar);

This spelled me bineeshkumar

Two dimensional arrays are created the same way single dimensional arrays are. And you access them like array[0][1].

var arr = [1, 2, [3, 4], 5];



alert (arr[2][1]); //alerts "4"

I'm not sure if anyone has answered this but I found this worked for me pretty well -

var array = [[,],[,]]

eg:

var a = [[1,2],[3,4]]

For a 2 dimensional array, for instance.

To create a 2D array in javaScript we can create an Array first and then add Arrays as it's elements. This method will return a 2D array with the given number of rows and columns.

function Create2DArray(rows,columns) {

   var x = new Array(rows);

   for (var i = 0; i < rows; i++) {

       x[i] = new Array(columns);

   }

   return x;

}

to create an Array use this method as below.

var array = Create2DArray(10,20);

Use Array Comprehensions

In JavaScript 1.7 and higher you can use array comprehensions to create two dimensional arrays. You can also filter and/or manipulate the entries while filling the array and don't have to use loops.

var rows = [1, 2, 3];

var cols = ["a", "b", "c", "d"];



var grid = [ for (r of rows) [ for (c of cols) r+c ] ];



/* 

         grid = [

            ["1a","1b","1c","1d"],

            ["2a","2b","2c","2d"],

            ["3a","3b","3c","3d"]

         ]

*/

You can create any n x m array you want and fill it with a default value by calling

var default = 0;  // your 2d array will be filled with this value

var n_dim = 2;

var m_dim = 7; 



var arr = [ for (n of Array(n_dim)) [ for (m of Array(m_dim) default ]] 

/* 

         arr = [

            [0, 0, 0, 0, 0, 0, 0],

            [0, 0, 0, 0, 0, 0, 0],

         ]

*/

More examples and documentation can be found here.

Please note that this is not a standard feature yet.

For one liner lovers Array.from()

// creates 8x8 array filed with "0"    

const arr2d = Array.from({ length: 8 }, () => Array.from({ length: 8 }, () => "0"));

Another one (from comment by dmitry_romanov) use Array().fill()

// creates 8x8 array filed with "0"    

const arr2d = Array(8).fill(0).map(() => Array(8).fill("0"));

My approach is very similar to @Bineesh answer but with a more general approach.

You can declare the double array as follows:

var myDoubleArray = [];

And the storing and accessing the contents in the following manner:

var testArray1 = [9,8]

var testArray2 = [3,5,7,9,10]

var testArray3 = {"test":123}

var index = 0;



myDoubleArray[index++] = testArray1;

myDoubleArray[index++] = testArray2;

myDoubleArray[index++] = testArray3;



console.log(myDoubleArray[0],myDoubleArray[1][3], myDoubleArray[2]['test'],) 

This will print the expected output

[ 9, 8 ] 9 123

I found below is the simplest way:

var array1 = [];   

array1[0][100] = 5; 



alert(array1[0][100]);

alert(array1.length);

alert(array1[0].length);

I had to make a flexible array function to add "records" to it as i needed and to be able to update them and do whatever calculations e needed before i sent it to a database for further processing. Here's the code, hope it helps :).

function Add2List(clmn1, clmn2, clmn3) {

    aColumns.push(clmn1,clmn2,clmn3); // Creates array with "record"

    aLine.splice(aPos, 0,aColumns);  // Inserts new "record" at position aPos in main array

    aColumns = ;    // Resets temporary array

    aPos++ // Increments position not to overlap previous "records"

}

Feel free to optimize and / or point out any bugs :)

Javascript does not support two dimensional arrays, instead we store an array inside another array and fetch the data from that array depending on what position of that array you want to access. Remember array numeration starts at ZERO.

Code Example:

/* Two dimensional array that's 5 x 5 



       C0 C1 C2 C3 C4 

    R0[1][1][1][1][1] 

    R1[1][1][1][1][1] 

    R2[1][1][1][1][1] 

    R3[1][1][1][1][1] 

    R4[1][1][1][1][1] 

*/



var row0 = [1,1,1,1,1],

    row1 = [1,1,1,1,1],

    row2 = [1,1,1,1,1],

    row3 = [1,1,1,1,1],

    row4 = [1,1,1,1,1];



var table = [row0,row1,row2,row3,row4];

console.log(table[0][0]); // Get the first item in the array

Below one, creates a 5x5 matrix and fill them with null

var md = ;

for(var i=0; i<5; i++) {

    md.push(new Array(5).fill(null));

}



console.log(md);

Here's a quick way I've found to make a two dimensional array.

function createArray(x, y) {

    return Array.apply(null, Array(x)).map(e => Array(y));

}

You can easily turn this function into an ES5 function as well.

function createArray(x, y) {

    return Array.apply(null, Array(x)).map(function(e) {

        return Array(y);

    });

}

Why this works: the new Array(n) constructor creates an object with a prototype of Array.prototype and then assigns the object's length, resulting in an unpopulated array. Due to its lack of actual members we can't run the Array.prototype.map function on it.

However, when you provide more than one argument to the constructor, such as when you do Array(1, 2, 3, 4), the constructor will use the arguments object to instantiate and populate an Array object correctly.

For this reason, we can use Array.apply(null, Array(x)), because the apply function will spread the arguments into the constructor. For clarification, doing Array.apply(null, Array(3)) is equivalent to doing Array(null, null, null).

Now that we've created an actual populated array, all we need to do is call map and create the second layer (y).

To create a non-sparse "2D" array (x,y) with all indices addressable and values set to null:

let 2Darray = new Array(x).fill(null).map(item =>(new Array(y).fill(null))) 

bonus "3D" Array (x,y,z)

let 3Darray = new Array(x).fill(null).map(item=>(new Array(y).fill(null)).map(item=>Array(z).fill(null)))

Variations and corrections on this have been mentioned in comments and at various points in response to this question but not as an actual answer so I am adding it here.

It should be noted that (similar to most other answers) this has O(x*y) time complexity so it probably not suitable for very large arrays.

You could allocate an array of rows, where each row is an array of the same length. Or you could allocate a one-dimensional array with rows*columns elements and define methods to map row/column coordinates to element indices.

Whichever implementation you pick, if you wrap it in an object you can define the accessor methods in a prototype to make the API easy to use.

I found that this code works for me:

var map = [

    

];



mapWidth = 50;

mapHeight = 50;

fillEmptyMap(map, mapWidth, mapHeight);

...

function fillEmptyMap(array, width, height) {

    for (var x = 0; x < width; x++) {

        array[x] = ;

        for (var y = 0; y < height; y++) {



            array[x][y] = [0];

        }

    }

}

A simplified example:

var blocks = ;



blocks[0] = ;



blocks[0][0] = 7;

One liner to create a m*n 2 dimensional array filled with 0.

new Array(m).fill(new Array(n).fill(0));

I've made a modification of Matthew Crumley's answer for creating a multidimensional array function. I've added the dimensions of the array to be passed as array variable and there will be another variable - value, which will be used to set the values of the elements of the last arrays in the multidimensional array.

/*

*   Function to create an n-dimensional array

*

*   @param array dimensions

*   @param any type value

*

*   @return array array

 */

function createArray(dimensions, value) {

    // Create new array

    var array = new Array(dimensions[0] || 0);

    var i = dimensions[0];



    // If dimensions array's length is bigger than 1

    // we start creating arrays in the array elements with recursions

    // to achieve multidimensional array

    if (dimensions.length > 1) {

        // Remove the first value from the array

        var args = Array.prototype.slice.call(dimensions, 1);

        // For each index in the created array create a new array with recursion

        while(i--) {

            array[dimensions[0]-1 - i] = createArray(args, value);

        }

    // If there is only one element left in the dimensions array

    // assign value to each of the new array's elements if value is set as param

    } else {

        if (typeof value !== 'undefined') {

            while(i--) {

                array[dimensions[0]-1 - i] = value;

            }

        }

    }



    return array;

}



createArray();              //  or new Array()



createArray([2], 'empty');    // ['empty', 'empty']



createArray([3, 2], 0);       // [[0, 0],

                              //  [0, 0],

                              //  [0, 0]]