I did some experiments...?

var numbers = [ 1, 2, 3, 4, 5, 6 ];
numbers[numbers.length ] = 7;
alert (numbers);
//output: 1, 2, 3, 4, 5, 6, 7

var evenNumbers = [2, 4, 6, 8, 10, 12 ];
evenNumbers[evenNumbers.length] = 14;
alert (evenNumbers);
//output: 2, 4, 6, 8, 10, 12, 14

var randomNumbers = [34, 21, 49, 2, 8, 208 ];
randomNumbers[randomNumbers.length] = 50;
alert (randomNumbers);
//output: 34, 21, 49, 2, 8, 208, 50 

var boolValues = [true, false, false, true, true];
boolValues[boolValues.length] = false;
alert (boolValues);
//output: true, false, false, true, true, false

var mixedValues = ["banana", "green", 45, false]
mixedValues[mixedValues.length] = "Hires";
alert (mixedValues);
//output: "banana", "green", 45, false, "Hires"