2. JavaScript is a programming language
designed for Web pages.
JavaScript is mainly client-side language and
runs in clients software.
Javascript was created by Brendan
Eich and was first introduced in December
1995.
3. Put text in an HTML page on-the-fly.
Make your web pages responsive.
Create cookies.
Validate web form data.
Detect visitors' browsers.
4. JavaScripts can reside in a separate page.
JavaScript can be embedded in HTML
documents -- in the <head>, in the <body>, or in
both.
JavaScript object attributes can be placed in
HTML element tags.
e.g., <body onLoad="alert('WELCOME')">
5. Linking can be advantageous if many pages use
the same script.
Use the source element to link to the script file.
<script type="text/javascript"
src="yourjavascript.js"></script>
6. When specifying a script only the tags <script>
and </script> are essential, but complete
specification is recommended:
<script type="text/javascript">
</script>
7. JavaScript programming uses specialized
terminology.
Understanding JavaScript terms is fundamental
to understanding the script.
Objects, Properties, Events, Functions, Variabl
es, Operators.
8. Objects refers to
windows, documents, images, tables, forms, buttons
or links, etc.
Objects should be named.
Objects have properties that act as modifiers.
9. Properties are object attributes.
Object properties are defined by using the object's
name, a period, and the property name.
e.g., background color is expressed by:
document.bgcolor .
document is the object.
bgcolor is the property.
10. onabort=Occurs when the user cancels loading of
an image.
onblur=Occurs when input focus is removed from a
form element (when the user clicks outside a field) or
focus is removed from a window.
onclick=Occurs when the user clicks on a link or
form element.
onchange=Occurs when the value of a form field is
changed by the user.
onerror=Occurs when an error happens during
loading of a document or image.
onfocus=Occurs when input focus is given to a form
element or a window.
11. onload=Occurs when a page is loaded into Navigator.
onmouseout=Occurs when the user moves the pointer
off of a link or clickable area of an image map.
onmouseover=Occurs when the user moves the
pointer over a hypertext.
onsubmit=Occurs when a form is submitted (i.e., when
the user clicks on a submit button).
onunload=Occurs when the user leaves a page
12. Functions are named statements that performs
tasks.
e.g., function doWhatever () {statement here}
The curly braces contain the statements of the
function.
JavaScript has built-in functions, and you can
write your own.
13. Variables contain values and use the equal sign
to specify their value.
Variables are created by declaration using the var
command with or without an initial value state.
e.g. var month;
e.g. var month = April;
14. Operators are used to handle variables.
Types of operators with examples:
Arithmetic operators, such as plus.
Comparisons operators, such as equals.
Logical operators, such as and.
Assignment and String operators.
