Javascript - split array into chunks

SplitArray.js

var myArray = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19, 20, 21];

function splitArray(array, numberOfChunks) { 
	
  arrayCount = array.length; 
  split = array.length / numberOfChunks; 
  
  
	chunks = [];
  
  for(j = 0; j < numberOfChunks; j++) { 
    var chunk = [];
    for(i = 0; i < split; i++) { 
        if (typeof array[i] !== 'undefined') { 
        	chunk.push(array[i]);
        } 
    }
    array.splice(0, chunk.length);

    chunks.push(chunk);
  }
  
  return chunks;

}

console.log(splitArray(myArray, 2));