The way I would describe an array to a novice is that it's a more complex and potentially useful type of variable, similar to the ones you've been making so far, only instead of having a single "slot" for data, they are organized in a way that allows for multiple slots for information, and you can reference each slot by their position in the array, starting with position 0 (0, 1, 2, etc. describing the first, second and third. etc. positions in the array).
An array is a variable declared with square brackets around all the data, with a comma in between (delimiting) each positioned slot of data.
Example:
var array = ["data1", "data2", "data3"]
In this case, we've created an array containing text strings. It could just as easily contain integers, or as you will see demonstrated a little later in the course, other variables, including other arrays.
Then, in order to retrieve or modify a piece of information from the array, you reference the array variable with the array position you want in square brackets.
Example: To get the "data1" string from the above array, use the variable like this:
array[0]
To get an alert dialog with the "data2" string, the code would look like:
alert(array[1])
You can easily modify a piece of data in the array using this technique. For example, to change the string "data3" in the array to "third", the code would be:
array[2] = "third"
If you would like to add a new piece of data to the array, you could do the following:
array[3] = "fourth"
Note that this would require that you know the size of the array and that the position [3] is an available slot. A simpler method of adding data to an array is to use the .push function as such:
array.push("fourth")