Function

Functions are chunks of code.Let's created a simple function:

     function test()
     {
     document.write("Hello can you see me?")
     }

Note that if only this were within your <script></script> tags, you will not see "Hello can you see me?" on your screen because functions are not executed by themselves until you call upon them. So we should do something:

     function test()
     {
     document.write("Hello can you see me?")
     }
     test() 

Last line"test()" calls the function, now you will see the words "Hello can you see me?".