An Array is a Data Type that can contain multiple values that we can call upon at any time within out code. Like an Object type, we have to define an array by calling its Constructor with the new keyword:
var mySet = new Array();
So here we have created an empty Array, though we can place any values we want into an array such as numbers, strings, or Booleans:
var mySet = new Array(25, “hello”, false);
To access values in an Array, we just need to call its name followed by square brackets, then define the index of the value we want. Now the index values in an Array start at Zero:
alert(mySet); // 25
alert(mySet); // “hello”
alert(mySet); // false
You can also reassign values to the array simply by calling them and giving a new value:
mySet = 10;
We just change the value of the first item in the Array from 25 to 10.
We can also add new values to an array by assigning a value to the next available index:
mySet = 18;
mySet = “something”;
Now you want to make sure you add to the last index of the Array, so you wouldn’t add to index  if your array only has 5 values. So to make sure that you always add to the end of the array we can get the length of the array first, which starts counting at 1 instead of Zero, meaning is will always be one number higher than the index:
mySet[mySet.length] = “a value”; // inserts value at index of 5
mySet[mySet.length] = “more values”; // inserts value at index of 6
There are also Methods that come with an Array for inserting values in this manner, such as the push method:
mySet.push(“a newer value”);
This method automatically finds the end of an Array and adds the new value too it.
There are many more Methods that can be used with an array which will be listed in the Reference Library, Such as concat(), join(), pop(), push(), reverse(), shift(), slice(), sort(), splice(), toString and unshift().