JavaScript Training in Ambala ! Batra Computer Centre

Today We’ll Learn
 Javascript
 What is javascript
 Are Java & Javascript the Same?
 How to put javascript in an HTML page
 Ending statement with a Semicolon?
 Javascript Variables
 Operators in Javascript
 Popup Boxes in javascript
Ph. No. :9729666670,4000670 Website: www.batracomputercentre.com

JAVASCRIPT
JavaScript is used in millions of Web pages to
improve the design, validate forms, detect
browsers, create cookies, and much more.
JavaScript is the most popular scripting
language on the internet, and works in all
major browsers, such as Internet Explorer,
Mozilla, Firefox, Netscape, Opera.

WHAT IS JAVASCRIPT
 JavaScript was designed to add interactivity to
HTML pages
 JavaScript is a scripting language (a scripting
language is a lightweight programming language)
 A JavaScript consists of lines of executable
computer code
 A JavaScript is usually embedded directly into
HTML pages
 JavaScript is an interpreted language (means that
scripts execute without preliminary compilation)
 Everyone can use JavaScript without purchasing a
license

Are Java And Javascript The
Same?
 NO!
 Java and JavaScript are two completely
different languages in both concept and
design!
 Java (developed by Sun Microsystems) is a
powerful and much more complex
programming language - in the same category
as C and C++.

How to put a javascrpit into an
HTML page
<html>
<body>
<script type="text/javascript">
document.write("Hello World!")
</script>
</body>
</html>

Ending Statement with a
Semicolon?
 With traditional programming languages, like
C++ and Java, each code statement has to end
with a semicolon (;).
 Many programmers continue this habit when
writing JavaScript, but in general, semicolons
are optional! However, semicolons are
required if you want to put more than one
statement on a single line.

Operators
in
Javascript
There are following important operators used in
Javascripts:
 Arithmetic Operator
 Assignment Operator
 Comparison Operator
 Logical Operator

Javascript Variables
 Variables are used to store data.
 A variable is a "container" for information you want
to store. A variable's value can change during the
script. You can refer to a variable by name to see its
value or to change its value.
 Rules for variable names:
• Variable names are case sensitive
• They must begin with a letter or the underscore character
o strname – STRNAME (not same)

Arithmetic Operator
 Arithmetic operators are used to perform
arithmetic between variables and/or values.
 Given that y = 5, the table below explains the
arithmetic operators:
– Addition
– Subtraction
– Multiplication
– Division
– Modulus
– Increment
– Decrement

Example

Assignment Operator
 Assignment operators are used to assign
values to JavaScript variables.
 The basic assignment operator is equal (=),
which assigns the value of its right operand to
its left operand. That is, x = y assigns the value
of y to x.
 Given that x = 10 and y = 5, the table below
explains the assignment operators:

Comparison Operator
 Comparison operators are used in logical
statements to determine equality or difference
between variables or values.
 JavaScript has both strict and type–converting
comparisons.
 The more commonly-used abstract comparison
(e.g. ==) converts the operands to the same
type before making the comparison.
 For relational abstract comparisons (e.g., <=),
the operands are first converted to primitives,
then to the same type, before comparison.

Logical Operator
 Logical operators are used to determine the
logic between variables or values.
 Logical operators are typically used
with Boolean (logical) values.
 However, the && and || operators actually
return the value of one of the specified
operands, so if these operators are used with
non-Boolean values, they may return a non-
Boolean value.

Popup Boxes in
Javascript
JavaScript has three kind of popup boxes:
 Alert box
 Confirm box
 Prompt box

Alert dailog Box
An alert dialog box is mostly used to give a
warning message to the users. For example, if
one input field requires to enter some text but
the user does not provide any input, then as a
part of validation, you can use an alert box to
give a warning message.

Output
After click on “Click
Me” =>

Confirmation Dialog Box
 A confirmation dialog box is mostly used to
take user's consent on any option. It displays a
dialog box with two buttons: Cancel.
 If the user clicks on the OK button, the
window method confirm() will return true. If
the user clicks on the Cancel button,
then confirm() returns false. You can use a
confirmation dialog box as follows.

Output
After click on “Click
Me” =>

Prompt Dialog Box
 The prompt dialog box is very useful when you want to
pop-up a text box to get user input. Thus, it enables you to
interact with the user. The user needs to fill in the field and
then click OK.
 This dialog box is displayed using a method
called prompt() which takes two parameters: (i) a label
which you want to display in the text box and (ii) a default
string to display in the text box.
 This dialog box has two buttons: OK and Cancel. If the user
clicks the OK button, the window method prompt()
will return the entered value from the text box.
 If the user clicks the Cancel button, the window
method prompt()returns null.

CONTACT US
BATRA COMPUTER CENTRE
SCO 15, Dayal Bagh,
Near Hanuman Mandir,
Ambala Cantt.
Phn No.: 9729666670,0171-4000670
Email: info.jatinbatra@gmail.com
Website: www.batracomputercentre.com

JavaScript Training in Ambala ! Batra Computer Centre

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