How to creating dynamic arrays?

var randomArrayPrefix = 'sample';
var randomArraySuffix = '_arr';
var totalArrayCount = 5;
for(var i = 0; i < totalArrayCount; i++) {
  var arrName = randomArrayPrefix + i + randomArraySuffix;
  if(typeof window[arrName] == 'undefined') {
    window[arrName] = [];
  }
}
document.write('Object name: Sample0_arr' + '<br/>');
document.write('Object type: ' + typeof sample0_arr + '<br/>');
document.write('Object size: ' + sample0_arr.length + '<br/>');
document.write('<br/>Other arrays are - <br/>');

for(ele in window) {
  if(ele.indexOf(randomArrayPrefix) >= 0) {
    document.write('Object name: ' + ele + '<br/>');
    document.write('Object type: ' + typeof window[ele] + '<br/>');
    document.write('Object size: ' + window[ele].length + '<br/>');
  }
}