CNIT 133

1
CNIT 133

• 3 ways to run JavaScript

2
Objectives

• Where do I put my JavaScript?
• JavaScript in URL
• JavaScript inside the ltbodygt
• Call a JavaScript function

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Where do I put my JavaScript?

• JavaScript is placed on your HTML page, and must
  be identified with a ltscriptgtlt/scriptgt
• ltscriptgt
• lt/scriptgt
• Often you will see this written as
• ltscript typetext/javascriptgt
• lt/scriptgt
• These script tags generally go in the
  ltheadgtlt/headgt section of your HTML page. The
  reason is that the browser reads this section
  first, and we will want most of our JavaScripts
  available for the entire page.
• Instead of actually putting the JavaScript into
  the HTML page, inline with the HTML code, you can
  write the code externally in a text file. The
  file should be named with a .js extension. Then
  your page would simply include the external
  code by using tags as follows
• ltscript srcmyscript.jsgt
• lt/scriptgt
• Code written this way has the advantage of being
  reusable. Code that needs to run on multiple
  pages on your site can now be written once and
  included on each page that needs it.

4
JavaScript in URL

• copy the following JS code and paste it in the
  URL, then hit the enter key. javascript var
  nownew Date() "lth1gt the time is lt/h1gt" now

5
JavaScript inside the ltbodygt

• Directly code the JS inside the body element.
  (Normally use the document.write() function to
  display the output) Inside the ltbodygt element
  ltscript language"javascript"gt var a 10
  ...... document.write("Resut is " a)
  lt/scriptgt

6
Call a JavaScript function

• From the body element, directly call a function
  defined inside the head element. (Normally use
  the alert() function to display output) Inside
  the head element (defines the function)ltscript
  language"javascript"gt function f1() var a
  10 ........... alert("Result is " a)
  lt/scriptgt Inside the body element (call the
  function) lta href"javascript f1()"gt Click to
  run JSlt/agt