4th Quarter Modules Flashcards
Is a light-weight object-oriented programming language which is
used by several websites for scripting the webpages.
JavaScript (js)
It is an interpreted, full-fledged
programming language that enables dynamic interactivity on websites when applied to
an HTML document.
JavaScript (js)
It was introduced in the year 1995 for adding programs to the
webpages in the Netscape Navigator browser.
JavaScript (js)
With __________, users can build modern web
applications to interact directly without reloading the page every time.
JavaScript
The name
was suggested and provided in the times when ____ was gaining popularity in the
market.
Java
Although, JavaScript has no ____________ with Java programming language.
connectivity
All popular web browsers support __________ as they provide built-in execution
environments.
JavaScript
__________ follows the syntax and structure of the C programming language.
Thus, it is a structured programming language.
JavaScript
is a weakly typed language, where certain types are implicitly cast
(depending on the operation).
JavaScript
is an object-oriented programming language that uses prototypes
rather than using classes for inheritance.
JavaScript
- It is a light-weighted and interpreted language.
- It is a case-sensitive language.
features of JavaScript
- is supportable in several operating systems including, Windows,
macOS, etc. - It provides good control to the users over the web browsers.
features of JavaScript
He realized that the web needed to
become more dynamic.
Marc Andreessen
In 19__, Mosaic, the first popular web browser, came into existence.
1993
In the year
19__, Netscape was founded by Marc Andreessen.
1994
Who founded Netscape?
Marc Andreessen
Thus, a ‘____ language’ was believed to be provided to HTML to
make web designing easy for designers and part-time programmers.
glue language
Consequently, in
19__, the company recruited _______ ____ intending to implement and embed Scheme
programming language to the browser.
1995 & Brendan Eich
But, before Brendan could start, the company
merged with ___ ____________ for adding Java into its Navigator so that it could
compete with Microsoft over the web technologies and platforms.
Sun Microsystems
Further, _________ decided to give a similar
name to the scripting language as Java’s.
Netscape
Finally, in May 1995, ____ __________ coined the first code of Javascript named ‘Mocha’.
Marc Andreessen
The marketing team replaced the name with ‘LiveScript’. But, due to
trademark reasons and certain other reasons, in December 1995, the language was
finally renamed to ‘___________’. From then, ___________ came into existence.
JavaScript
- Client-side validation,
- Dynamic drop-down menus,
- Displaying date and time,
- Displaying pop-up windows and dialog boxes (like an alert dialog box, confirm
dialog box and prompt dialog box), - Displaying clocks etc.
Application of JavaScript
3 JavaScript Index
- JavaScript Introduction
- JavaScript Example
- External JavaScript
9 JavaScript Basics
- JavaScript Comment
- JavaScript Variable
- JavaScript Global Variable
- JavaScript Data Types
- JavaScript Operators
- JavaScript If Statement
- JavaScript Switch
- JavaScript Loop
- JavaScript Function
3 Places to put JavaScript code
- Between the body tag of html
- Between the head tag of html
- In .js file (external javaScript)
JavaScript Example :
alert("Hello Javatpoint");
code between the body tag
JavaScript Example :
In this example, we are creating a function msg(). To create function in JavaScript, you
need to write function with function_name as given below.
code between the head tag
<html>
<head>
<script>
function msg()
{
alert("Hello Javatpoint");
}
</script>
</head>
<body>
<p>Welcome to JavaScript</p>
<form>
<input></input>
</form>
</body>
</html>
onclick event to call
msg() function
An external JavaScript file must be saved by ___ extension.
.js
We can create external JavaScript file and ______ it in many html page.
embed
It provides
code re usability because single JavaScript file can be used in several html pages.
External JavaScript file
It helps in the reusability of code in more than one HTML file.
Advantages of External JavaScript
It allows easy code readability.
Advantages of External JavaScript
It is time-efficient as web browsers cache the external js files, which further
reduces the page loading time.
Advantages of External JavaScript
It enables both web designers and coders to work with html and js files
parallelly and separately, i.e., without facing any code conflictions.
Advantages of External JavaScript
The length of the code reduces as only we need to specify the location of the js
file.
Advantages of External JavaScript
If two js files are dependent on one another, then a failure in one file may affect
the execution of the other dependent file.
Disadvantages of External JavaScript
The stealer may download the coder’s code using the url of the js file.
Disadvantages of External JavaScript
The web browser needs to make an additional http request to get the js code.
Disadvantages of External JavaScript
A tiny to a large change in the js code may cause unexpected results in all its
dependent files.
Disadvantages of External JavaScript
We need to check each file that depends on the commonly created external
javascript file.
Disadvantages of External JavaScript
If it is a few lines of code, then better to implement the internal javascript code.
Disadvantages of External JavaScript
Is ignored by the JavaScript engine i.e. embedded in the
browser.
JavaScript comment
- To make code easy to understand It can be used to elaborate the code so that
end user can easily understand the code. - To avoid the unnecessary code It can also be used to avoid the code being
executed. Sometimes, we add the code to perform some action. But after
sometime, there may be need to disable the code. In such case, it is better to
use ________.
Advantages of JavaScript comments
- Single-line and Multi-line comments
- The JavaScript comments are meaningful way to deliver message. It is used to
add information about the code, warnings or suggestions so that end user can
easily interpret the code.
JavaScript Comment
Advantage of javaScript comments
two types of comments in JavaScript.
- Single-line Comment
- Multi-line Comment
JavaScript variables are
case __________, for example x and X are different variables.
sensitive
It is represented by double forward slashes (//). It
can be used before and after the statement.
JavaScript Single line Comment
Is simply a name of storage location.
JavaScript variable
two types of
variables in JavaScript
local variable and global variable
(a to z or A to Z), underscore( _ ), or dollar( $ ) sign.
After first letter we can use digits (0 to 9), for example value1.
rules while
declaring a JavaScript variable (also known as identifiers).
Is declared inside block or function. It is accessible within
the function or block only. For example:
<script>
function abc()
{
var x=10;//local variable
}
</script>
Or,
<script>
If(10<13)
{
var y=20;//JavaScript local variable
}
</script>
JavaScript local variable
Is accessible from any function. A variable i.e. declared
outside the function or declared with window object is known as global variable. For
example:
<script>
var data=200;//gloabal variable
function a(){
document.writeln(data);
}
function b(){
document.writeln(data);
}
a();//calling JavaScript function
b();
</script>
JavaScript global variable
Provides different data types to hold different
types of values.
JavaScript
Is a dynamic type language, means you don’t need to
specify type of the variable because it is dynamically used by __________ engine.
JavaScript
types of data types in JavaScript.
- Primitive data type
- Non-primitive (reference) data type
Data Type:
represents sequence of characters e.g. “hello”
String
Data Type:
represents numeric values e.g. 100
Number
Data Type:
represents boolean value either false or true
Boolean
Data Type:
represents undefined value
Undefined
Data Type:
represents null i.e. no value at all
Null
Data Type:
represents instance through which we can access members
Object
Data Type:
represents group of similar values
Array
Data Type:
represents regular expression
RegExp
Are symbols that are used to perform operations on operands.
JavaScript operators
Are used to perform
arithmetic operations on the operands.
JavaScript Arithmetic Operators
Operators in Javascript
- Arithmetic Operators
- Comparison (Relational) Operators
- Bitwise Operators
- Logical Operators
- Assignment Operators
- Special Operators
compares
the two operands.
JavaScript Comparison Operators
perform bitwise operations on
operands.
JavaScript Bitwise Operators
