Javascript lines end with a semicolon. You may have noticed from the example on the previous page that javascript lines end with a semicolon. You can easily put all your javascript on a single line without destroying the performance of it. However, you would destroy the overview of your script so it is not advisable. In the next section you will learn why this would cause an error to your script.
Capital letters are different from lowercase letters.
You should always remember that capital letters are different from lowercase letters. This means that when you write commands in javascript, you need to type capital letters in the correct places, and nowhere else. F or instance, one javascript command is called onMouseOver . If you typed Onmouseover instead, you might as well have typed qwHETweriuh since javascript just doesn't understand it. T he document.write is a javascript command telling the browser that what follows within the parentheses is to be written into the document.