2. Objective
Introduction to jscript.
Difference between Jscript, JavaScript and
2
VBScript.
Versions.
Programming logic techniques of the Jscript.
Writing Jscript statements and coding.
OOPs Concept.
Understanding JScript objects.
Working with methods .
The JScript object hierarchy.
Practice Examples
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3. Topics has to be covered…
Day 1
Introduction to jscript.
Javascript vs jscript and other
scripting languages.
Versions.
Day 2
OOPs Concept
Understanding JScript objects
Array handling
Exception Handling
Array Object
Error Object
The role of objects in JScript
programming
Programming logic techniques Working with methods and
of the Jscript
properties
Writing Jscript statements and The JScript object hierarchy
coding
String Handling
Object Literals
3
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4. What Is script ?
In computer programming, a script is a program
4
or sequence of instructions that is interpreted or
carried out by another program rather than by the
computer processer (as a compiled program is).
A script is sometimes used to mean a list of
operating system commands that are pre-stored
in a file and performed sequentially by the
operating system's command interpreter
whenever the list name is entered as a single
command.
Multimedia development programs use "script" to
mean the sequence of instructions that you enter
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to indicate how a multimedia sequence of files will
5. What Is scripting language ?
A scripting language is a form of programming
5
language that is usually interpreted rather than
compiled.
Conventional programs are converted
permanently into executable files before they are
run. In contrast, programs in scripting language
are interpreted one command at a time.
Scripting languages can be used to create
specialized GUIs (graphical user interfaces) and
forms that enhance the convenience of search
engines, Web-based e-mail and e-commerce.
For Example: C
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shell, JavaScript, Jscript, Perl, PHP, Python, VBS
6. Introduction of JScript
JScript is a scripting language from Microsoft that is
expressly designed for use within Web pages. It
adheres to the ECMAScript standard and is basically
Microsoft's equivalent to Netscape's earlier and more
widely used JavaScript.
ECMAScript (European Computer Manufacturers
Association Script)
ECMAScript is a standard script language, developed
with the cooperation of Netscape and Microsoft and
mainly derived from Netscape's JavaScript, the widelyused scripting language that is used in Web pages to
affect how they look or behave for the user.
ECMAScript is object-oriented and conceived as a core
language to which can be added the objects of any
6
specific domain or context such as the idea of a 10/15/2013
7. Using JScript
JScript is an interpreted, object-based scripting
language. Although it has fewer capabilities than fullfledged object-oriented languages like C++, JScript is
more than sufficiently powerful for its intended
purposes.
JScript is not a cut-down version of another language
(it is only distantly and indirectly related to Java, for
example), nor is it a simplification of anything.
You cannot write stand-alone applications in it, and it
has no built-in support for reading or writing files.
Jscript scripts can run only in the presence of an
interpreter or "host", such as Active Server Pages
(ASP), Internet Explorer, or Windows Script Host.
7
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8. JavaScript Vs JScript Vs VBScript
JavaScript
JavaScript is a light weight and very simple Scripting Language
that has Object Oriented capabilities and most importantly it is a
cross platform Scripting Language.
These scripts can be integrated directly into the HTML code.
JavaScript was originally developed by Netscape.
Here is a simple example showing a text in a web page using
JavaScript.
<html>
<body>
<script type="text/javascript">
{
document.write("Hello JavaScript");
}
</script>
</body>
</html>
8
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9. Jscript
Actually JScript is just the Microsoft's version of
JavaScript. Microsoft thought of implementing their own
version of JavaScript and they named it as JScript.
But in some situations JScript is not behaving like
JavaScript.
Take a simple example: Let's declare a variable called
temp in JavaScript code and create a object within the
page having the field id as "temp".
var temp = 'Hello';
And trying to set the value of object temp in the page to
the value of variable temp.
document.getElementById('temp').innerHTML = temp;
9
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10. Cont…
In the above example, is working fine, but the JScript gives a
error.
reason behind this is, in here JScript does not recognize the
difference between var
temp and document.getElementById('temp'). So he treats as
both of them are referring to one single object. But
JavaScript recognises the temp variable and the object within
the page having id "temp" as two entirely separate fields.
So this is a one significant difference between JavaScript and
JScript.
here is a simple example showing a text in a web page using JScript.
10
<html>
<body>
<script type="text/JScript">
{
document.write("Hello JScript");
}
</script>
</body>
</html>
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11. VBScript
VBScript is Microsoft's Scripting Language just as JScript.
It is actually a child of Microsoft's Visual Basic for use with
web pages and other applications that uses Microsoft
ActiveX controls.
VBScript is very similar to JavaScript, but VBScript
syntaxes are more similar to Visual Basic.
Comparison of JavaScript and VBScript
11
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12. Cont…
Similarities
Differences
Both languages are easy to learn and
do not require any expensive
development tools.
JavaScript is the default scripting
language for browsers but VBScript
must be specified as the scripting
language.
Both can be used to enhance web
pages.
JavaScript has cross-platform support
from all popular browsers while
VBScript is supported MS IE only.
Both can abuse and run malicious
scripts on clients' machines.
JavaScript is case sensitive but
VBScript is not this would not be
prone to as many syntax errors like
missing >
JavaScript uses the same character
for concatenation as it does for
addition (the + character) while the '&'
concatenating character is used in
VBScript. This is another source of
errors in JavaScript.
12
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13. Cont…
Here is a simple example showing a text in a web
page using VBScript.
<html>
<body>
<script type="text/vbscript">
{
document.write("Hello VBScript");
}
</script>
</body>
</html>
13
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14. Version
The following table lists the version of Microsoft JScript implemented by host
applications.
Host application
JScript version
Internet Explorer 3.0
Internet Information Server 3.0
2.0
Internet Explorer 4.0
3.0
Internet Information Server 4.0
3.0
Visual Studio 6.0
4.0
Internet Explorer 5.0
5.0
Internet Explorer 5.01
5.1
Windows 2000
5.1
Internet Explorer 5.5
5.5
Internet Explorer 6.0
5.6
Windows XP (through SP2)
5.6
Internet Explorer 7.0
5.7
Windows XP SP3
14
1.0
5.7
Windows Vista
5.7
Internet Explorer 8.0
5.8
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15. Applications Fundamentals
Practical Learning: Adding the Compiler to the Path
Start Windows Explorer and locate the folder where
your jsc application is installed. Here is an example:
15
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16. Cont…
Click Start -> Control Panel
Double-click System
In the System Properties dialog box, click the Advanced
16
tab and click Environment Variables
In the System Variables section, click Path and click
Edit
Press End or get to the end of the string
Type ; followed by the complete path to the compiler.
Click OK on each dialog box
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17. Practical Learning: Introducing Jscript
Code
Start Notepad and in it, type print("Welcome to the
17
Wonderful World of JScript ");
To save the file, on the main menu, click File -> Save
Select and display the C: drive in the Save In combo box
Click the Create New Folder button
Type JScript Lessons
Press Enter twice or display the new folder in the Save In
combo box
Click the Create New Folder button again
Type Exercise1 and press Enter twice or display the new
folder in the Save In combo box
Save the file as exercise.js
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18. Practical Learning: Compiling an
Application
To test the application, open the Command Prompt
and change to the folder in which you created the
Jscript file.
18
•Type jsc exercise.js and press Enter
•When the program has finished compiling,
type exercise and press Enter
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19. A Custom Name for an Executable
As mentioned above, if you compile your application by
simply invoking the name of the script file that contains
the code, an executable with the same name as the file
would be created.
Fortunately, when compiling the file, you can specify the
name you want for the executable.
jsc /out:ApplicationName File.js
you must first call the compiler as done previously. It must be
followed by /out: which indicates that you are going to specify the
name of the executable.
After the /out: factor, type the desired name that will hold the name
of the new application instead of the name of the file.
Lastly, type the name of the file that contains the script and make
sure you append its extension.
19
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20. To compile with debugging information
using jsc
At the command prompt, type
jsc /debug file.js
The command compiles the program
named file.js with the /debug option to produce the
executable named file.exe and a file
named file.pdb that contains debugging information.
http://msdn.microsoft.com/enus/library/0h6706k6(v=vs.71).aspx
Debugging JScript with Visual Studio
http://msdn.microsoft.com/enus/library/bssx024s%28v=vs.80%29.aspx
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21. Programming logic techniques of the
Jscript
Variables
Statements
Data types
Comments
Operators and its Precedence
Controlling Program flow
Jscript reserve words
Conditions and Loops
21
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22. Variables
A typical program uses various and different values.
Some are used for display to the user. Some are
requested from the user.
To manage these various values, the compiler reserves
some sections of the computer memory to store them.
To declare a variable, type var, followed by a name for
the variable, followed by a colon, and followed by a
word that defines the type of value that would be stored
in this memory space.
ovar VariableName : DataType;
This means that, to declare a variable, you must
22
provide a name and specify the type of information the
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variable will carry.
23. Identifiers
An identifier is a word that is used to identify an entity in
a program. There are rules you must follow when
naming your variables. They are:
The first character must be a letter
(a, b, c,…, z, A, B, C, …, or Z) or an underscore (_).
Examples are _pages, country, or sound
After the first character, the name can contain
letters, underscores, or digits (0, 1, 2, 3,…, or 9).
Examples are number1, _page6, complete_sound
The complete name must not be one of the words
reserved for the compilers own use
23
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24. Cont…
JScript is case-sensitive. This means that
case, CASE, and Case are three different words. Based
on these rules, avoid using the following reserved words
to name your variables:
abstract
char
default
export
break
const
do
false
byte
continue
double
final
for
24
boolean
class
delete
extends
function
get
if
in
new
return
super
typeof
while
instanceof
null
sbyte
switch
uint
with
int
package
set
this
ulong
interface
private
short
throw
ushort
case
debugger
else
finally
implement
s
internal
protected
static
true
var
catch
decimal
enum
float
import
long
public
try
void
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25. Comments And Escape Sequence
A comment is a line or paragraph of text that the
compiler would not consider when examining the code
of a program.
To display a comment on a line of text, start the line
with two forward slashes //. Anything on the right side
of // would be ignored. Here is an example:
// This line will be ignored. I can write in it anything I
want
The above type of comment is used on only one line.
You can also start a comment with /*. This type of
comment ends with */.
Anything between this combination of /* and */ would
not be read by the compiler. Therefore, you can 10/15/2013
use
25
this technique to span a comment on more than one
26. Escape Sequences
An escape sequence is a special character that
displays non-visibly. For example, you can use this
type of character to indicate the end of line, that is,
to ask the program to continue on the next line.
An escape sequence is represented by a backslash
character, , followed by another character or
symbol. For example, the escape sequence that
moves to the next line is n.
An escape can be included in single-quotes as in
'n'. It can also be provided in double-quotes as "n".
26
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27. Cont…
Escape Sequence
Name
b
Backspace
t
Horizontal Tab
n
New line
v
Vertical Tab
f
Form feed
r
Carriage return
Causes a carriage return
s
Any Character
Matches any white space character
S
Any Character
Matches any non-white space character
'
Single Quote
Displays a single quote
"
Double Quote
Displays a double quote
Backslash
Displays a backslash ()
h
Character
xhh
2-Digit Hex
xhhhh
4-Digit Hex
27
Description
Takes the cursor back by one space
Takes the cursor to the next tab stop
Takes the cursor to the beginning of the
next line
Performs a vertical tab
Displays an ASCII character from an octal
number
Displays a hexadecimal number with two
digits
Displays a hexadecimal number with four
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digits
28. Data Types
A data type is a word that indicates the amount of
memory needed to store the value of a variable.
As there are various types of values used in a program,
there are also different data types. Some data types are
meant to hold numbers. Some others are form particular
values such as one being true or false.
In short, data types are specifications of how to handle
variables. The interpreter needs to know how much
memory he shall reserve for the data, and what can be
done with these.
28
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29. Cont…
Data Type
Description
Example
Char
a single character,
enclosed in single
quotation marks
var c: char = ’a’;
String
a sequence of
characters, enclosed in
double quotation marks
var s: String = "Hello";
Int
a 32-bit integer value,
ranging from 2.147.483.648 to
2.147.483.647
var i: int = 1;
Uint
a unsigned 32-bit integer,
ranging from 0 to
4.294.967.295
var i: uint = 1;
Boolean
a boolean value that is
either true or false
var b: boolean = false;
Double
floating point number of
double precision (about
15 digits)
var d: double = 0.123;
object representing a
var date: Date
29
Date
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30. Type mismatch
import System;
var s: int = 3;
s = s + 5;
Console.WriteLine(s);
s = "I’m not an integer!";
Console.WriteLine(s);
import System;
var s = 5;
s = "I’m a string!";
s = s + 3;
Console.WriteLine(s);
NOTE: If you do not initialize a variable, i.e. if you declare a variable
without setting it to a certain value, requesting the value will return NaN
(Not a Number) or ”undefined”, depending on the context in which the
variable was interpreted. For example,
import System;
var i;
Console.WriteLine( "Value of i: " + i);
Console.WriteLine( "Value of 2*i: " + 2*i);
will produce the output ”Value of i: undefined” and ”Value of i: NaN”,
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30
because in the first case we have a type conversion to string, in the
31. Operators and Operands
An operation is an action performed on one or more
values either to modify the value held by one or both of
the variables, or to produce a new value by combining
existing values.
Therefore, an operation is performed using at least one
symbol and at least one value. The symbol used in an
operation is called an operator. A value involved in an
operation is called an operand.
A unary operator is an operator that performs its
operation on only one operand. An operator is referred to
as binary if it operates on two operands.
31
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33. Operator Precedence
Operator
Description
. [] ()
Field access, array indexing, and function calls
++ -- - ~ ! typeof new void delete Unary operators, return data type, object creation, undefined values
*/%
Multiplication, division, modulo division
+-+
Addition, subtraction, string concatenation
<< >> >>>
Bit shifting
< <= > >=
Less than, less than or equal to, greater than, greater than or equal to
== != === !==
Equality, inequality, identity, nonidentity
&
Bitwise AND
^
Bitwise XOR
|
Bitwise OR
&&
Logical AND
||
Logical OR
?:
Conditional
= OP=
Assignment, assignment with operation
33
,
Multiple evaluation
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34. Sample Example
import System;
var a: boolean = true;
var b: boolean = false;
Console.WriteLine("a AND b = " + (a && b));
Console.WriteLine("a OR b = " + (a || b));
Output:
”a And b = false”
”a OR b = true”
34
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35. Program Flow
if..else-statements
import System;
var i=Math.random();
if (i<0.5) Console.WriteLine("This number " + i + " is smaller than 0.5");
else Console.WriteLine("This number " + i + " is larger than or equals
0.5");
Here, the code following the if-condition is executed
if the condition is true, and the code following the
else-statement is executed if the statement is false.
This is what you should notice:
35
• the boolean expression has to be set in parenthesis
• the if-clause here only consists of one command. It has to be closed
by a semicolon
• the else-clause also only consists of one command and has10/15/2013
to be
closed by a semicolon
36. for-Loops
The for-loops allow to repeat a command or block of
code for a certain time. Usually, a counter is counted up
until a certain condition does not hold any more.
import System;
var i;
for (i=1;i<10;i++) Console.WriteLine("This is the " + i + ".
line.");
for..in-Loops
import System;
var weekday = ["monday", "tuesday", "wednesday",
"thursday"];
var j;
for (j in weekday) Console.WriteLine(weekday[j]);
36
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37. while-Loops
The while-loops are similar to the for-loops, but the
header of the while loop has no section for
initializing and no section for incrementation, but just
the section for a comparison, the while-condition.
37
import System;
var steps = 10;
while (steps >= 1) {
if (steps > 1) Console.WriteLine(" There are" +
steps + " to do.");
else Console.WriteLine("Now there is only one
more step");
steps--;
}
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38. do...while
do...while loop in JScript that is similar to the while
loop, except that it is guaranteed to always execute at
least once, since the condition is tested at the end of the
loop, rather than at the start.
38
import System;
var x = 0;
do
{
x = Console.WriteLine("What is my favourite
number?", x);
} while ((x != 42) && (x != null));
if (x == null)
Console.WriteLine("You gave up!");
else
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39. Functions
A function is a piece of code that is encapsulated and
can be executed by calling the command under which
the function is defined.
JScript supports two kinds of functions: those that are
built into the language, and those you create yourself.
o Special Built-in Functions
The JScript language includes several built-in functions.
Some of them let you handle expressions and special
characters, and convert strings to numeric values.
For example, escape() and unescape() are used to
convert characters that have special meanings in HTML
code, characters that you cannot just put directly into
text. For example, the angle brackets, "<" and ">",
delineate HTML tags.
39
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40. Cont…
•Escape function: Encodes String objectsthese
The escape function takes as its argument any of so
special characters, and all computers.
they can be read onreturns the escape code for the
character. Each escape code consists of a percent sign
•The escape method returns a string value
(%) followed by a two-digit number.
(in Unicode format) that contains the
The unescape function is the exact inverse. It takes as
contents ofacharstring. All spaces, sign and a
its argument string consisting of a percent
punctuation, accented characters, and any other
two-digit number, and returns a character.
non-ASCII characters are replacedwhich %xx
Another useful built-in function is eval(), with
evaluates where mathematical expression
encoding, any validxx is equivalent to thethat is
presented in string form. The eval() function character.
hexadecimal number representing thetakes one
argument, the expression to be evaluated.
For example,anExpression = "6 * 9returned as "%20.“
a space is % 7";
• var
• var total = a value greater than 255 the
•Characters with eval(anExpression); // Assigns the value 5 toare
variable total.
stored using yetAnotherExpression = "6 * (9 % 7)";
• var the %uxxxx format.
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40
• total = eval(yetAnotherExpression); //Assigns the encoded
•Unescape Method: Decodes String objectsvalue 12 to
41. Creating Your Own Functions
You can create your own functions and use them where
you need them. A function definition consists of a
function statement and a block of JScript statements.
For Example:
import System;
function factorial(n)
{
var i;
var f=1;
for (i=1;i<=n;i++) f=f*i;
return f;
}
Console.WriteLine(factorial(8));
41
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42. Wait functions
42
// The namespace "System.Threading" provides
the "Thread"-class which
// includes the "Sleep"-method
import System.Threading;
var i;
for (i=0; i<=5; i++)
{
// Wait for 500 ms
Thread.Sleep(500);
// Display the variable i in the Output window
System.Console.WriteLine("Number: "+i);
}
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43. JScript Objects
JScript objects are collections of properties and
methods.
A method is a function that is a member of an object,
and a property is a value or set of values (in the form of
an array or object).
Objects as Arrays
In JScript, objects and arrays are handled identically.
You can refer to any of the members of an object :
o either by name (using the name of the object, followed by a
period, followed by the name of the property)
o or by its array subscript index.
All objects in JScript support "expando" properties, or
properties that can be added and removed dynamically
at run time.
43
• var myObj = new Object();
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44. Cont…
The fact that objects can have other objects as
properties lets you generate arrays with more than one
subscript, which are not directly supported. The following
code creates a multiplication table for values from 0
times 0 through 16 times 16.
var multTable = new Array(17); // Make the shell that will become the
table.
for (var j = 0; j < multTable.length; j++) { // Prepare to fill it with rows.
var aRow = new Array(17); // Create a row.
for (var i = 0; i < aRow.length; i++) { // Prepare to fill the row.
aRow[i] = (i + " times " + j + " = " + i*j); // Make and place one value.
}
multTable[j] = aRow; // Put the filled row into the table.
Console.WriteLine(multTable[j]);
}
44
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45. JScript Reserved Keywords
JScript has a number of reserved keywords that you
cannot use as identifiers.
These words come in three types: JScript reserved
keywords, future reserved words, and words to avoid.
Reserved words have a specific meaning to the JScript
language, as they are part of the language syntax.
Using a reserved word causes a compilation error when
loading your script.
JScript also has a list of future reserved words. These
words are not currently part of the JScript language,
although they are reserved for future use.
45
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47. Recursion
Recursion is an important programming technique. It is
used to have a function call itself from within itself.
One handy example is the calculation of factorials. The
factorials of 0 and 1 are both defined specifically to be
1.
The factorials of larger numbers are calculated by
multiplying 1 * 2 * ..., incrementing by 1 until you reach
the number for which you're calculating the factorial.
Recursion and iteration (looping) are strongly related anything that can be done with recursion can be done
with iteration, and vice-versa.
47
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48. Cont…
Here is the factorial function again, this time written in
JScript code.
48
// Function to calculate factorials. If an invalid
// number is passed in (ie, one less than zero), -1
// is returned to signify an error. Otherwise, the
// number is converted to the nearest integer, and its
// factorial is returned.
function factorial(aNumber) {
aNumber = Math.floor(aNumber); // If the number is not an integer,
round it down.
if (aNumber < 0) { // If the number is less than zero, reject it.
return -1;
}
if (aNumber == 0) { // If the number is 0, its factorial is 1.
return 1;
}
else return (aNumber * factorial(aNumber - 1)); // Otherwise, recurse
until done.
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}
49. Variable Scope
JScript has two scopes: global and local.
If you declare a variable outside of any function
definition, it is a global variable, and its value is
accessible and modifiable throughout your program.
If you declare a variable inside of a function definition,
that variable is local.
It is created and destroyed every time the function is
executed; it cannot be accessed by anything outside the
function.
A local variable can have the same name as a global
variable, but it is entirely distinct and separate.
Consequently, changing the value of one variable has
no effect on the other. Inside the function in which the
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49 local variable is declared, only the local version has
50. Example:
50
var aNumber = 100;
var withAdditive = 0;
withAdditive += aNumber; // withAdditive is now
100.
tweak();
withAdditive += aNumber; // withAdditive is now
200.
function tweak() {
var newThing = 0; // Explicit declaration of the
newThing variable.
aNumber = 42;
if (false) {
var aNumber; // This statement is never executed.
aNumber = "Hello!"; // This statement is never
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executed.
51. Special Characters
JScript provides special characters that allow you to
include in strings some characters you cannot type
directly.
Each of these characters begins with a backslash. The
backslash is an escape character you use to inform the
JScriptEscape Sequence the next character is special.
interpreter that
Character
b
n
Line feed (new line)
r
Carriage return
t
Horizontal tab (Ctrl-I)
’
Single quotation mark
”
Double quotation mark
51
Backspace
Backslash
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52. Exception Handling
try...catch.finally Statement
The try...catch.finally statement provides a way to
handle some or all of the possible errors that may
occur in a given block of code, while still running code.
If errors occur that the programmer has not
handled, Jscript simply provides its normal error
message to a user, as if there was no error handling.
52
try {
tryStatements
//Required. Statements where an error
can occur.
}
catch(exception){
catchStatements
//Required. Any variable name.
The initial value of exception is the value of
the thrown error.
} //Optional. Statements to handle errors occurring in the
associated
tryStatements.
finally {
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finallyStatements
//Optional. Statements that are
53. Example
The following example shows how JScript exception handling works.
53
try {
print("Outer try running..");
This produces the following output
try {
print("Nested try running..."); Outer try running..
Nested try running...
throw "an error";
Nested catch caught an error
}
Nested finally is running...
catch(e) {
Outer
print("Nested catch caught " + e); catch caught an error rethrown
throw e + " re-thrown";
Outer finally running
}
finally {
print("Nested finally is running...");
}}
catch(e) {
print("Outer catch caught " + e);}
finally {
print("Outer finally running");}
// Change this for Windows Script Host to say
Programming Concepts Compared in Different Languages with Code Examp
WScript.Echo(s)
http://msdn.microsoft.com/en-us/library/we7h0cz1%28v=vs.80%29.aspx
function print(s){
10/15/2013
document.write(s);}
