Download Javascript

JAVASCRIPT DEFINED
JavaScript Basics Definitions
JavaScript is an object-oriented programming language designed for
the world wide web. JavaScript code is embedded directly into
common HTML documents and is interpreted by the web browser when
the document is loaded. JavaScript allows web developers to include
high levels of interactivity in web pages.


Broad support among web browsers (enabled by
default)
Libraries of scripts available

Allows use of reusable code libraries

Similar syntax to C, C++, and Java

Encourages creative problem solving
WHY LEARN JAVASCRIPT?

Enhance interactivity (mouseover swap, games
etc).

Provide interesting visual effects (image
sliders,snow falling, cursor trails).

Provide tooltips on “focus”.

Validate forms for accurate data.
SOME EXAMPLES OF USAGE
PROGRAMMING LANGUAGES I
 Each
programming language was created to solve
some type of particular problem. There are hundreds
of programming languages. The instructions in a
computer program tell the computer what steps to
take to solve a problem.
 Programming
languages specify an exact sequence
or order of operations. Program logic determines the
next step to execute in a procedural language and
this logic determination is made in response to
conditions and user action. The traditional procedural
languages include but are not limited to: BASIC, C,
COBOL, FORTRAN, Pascal, C++.

"Compiled language" means the source code of
the program is translated (compiled) into machinelanguage (composed only of 0's and 1's) before
use. When it is time to run the program, the
translated version is used by the computer instead
of the original source code. Unless you are the
programmer, you might never see the source code
of the program you are using.
"Interpreted language" means when it loads a
page, the browser's interpreter uses the original
source code and translates it into machine
language. The translation is stored in the browser's
memory ready to run all or portions of it as
appropriate. When the browser window gets ready
to load a different web page, the previous page's
translated JavaScript is discarded.
COMPILED VS INTERPRETED
HOW THE BROWSER KNOWS IT IS JAVASCRIPT:
JavaScript code must be between <script...> </script> tags
or situated in an external .js file.
In XHTML/HTML 4 the text attribute is required:
<script type="text/javascript">
// javascript code is located between the opening and closing script
tags.
</script>
In HTML 5 the text attribute is optional:
<script>
// javascript code is located between the opening and closing script
tags.
</script>
Comments:
// This is a single-line javaScript comment.
/* This is a multi-line
javascript comment */
USING JAVASCRIPT WITH
EXPRESSION WEB
 As
web designers we work in code view.*
 We
copy the javascript code from the source.
 Following
directions of the programmer, we paste the
code into the head or body of the html document that is
open in EW.
 If
images are required for the script, we save them to our
flashdrive and import them into EW.
 Some
scripts provide variables that we can modify to our
specific needs.
*Exception to this is the EW Behaviors task pane
JAVASCRIPT
EXAMPLES