• Thursday , 27 July 2017

JavaScript Basics

Code Canyon



Link for all dot net and sql server video tutorial playlists
http://www.youtube.com/user/kudvenkat/playlists

Link for slides, code samples and text version of the video
http://csharp-video-tutorials.blogspot.com/2014/11/javascript-basics.html

In this video we will discuss
1. Is JavaScript case sensitive
2. Comments in JavaScript
3. Data types in JavaScript

Is JavaScript case sensitive
Yes, JavaScript is case sensitive programming language. Variable names, keywords, methods, object properties and event handlers all are case sensitive.

Example 1 : alert() function name should be all small letters
[script] alert(“JavaScripts Basics Tutorial”);
[/script]

Example 2 : Alert() is not same as alert(). Throws Alert is not defined error. To see the error press F12 key.
[script] Alert(“JavaScripts Basics Tutorial”);
[/script]

Comments in JavaScript : There are 2 types of comments in JavaScript.
1) Single Line Comment

Example :
[script] // This is a sinle line comment
[/script]

2) Multi Line Comment

Example:
[script] /* This is a
multi line
comment */
[/script]

Data types in JavaScript

The following are the different data types in JavaScript
Numbers – 5, 5.234
Boolean – true / false
String – “MyString”, ‘MyString’

To create a variable in JavaScript use var keyword. Variable names are case sensitive.

In c# to create an integer variable we use int keyword
int X = 10;

to create a string variable we use string keyword
string str = “Hello”

With JavaScript we always use var keyword to create any type of variable. Based on the value assigned the type of the variable is inferred.
var a = 10;
var b = “MyString”;

In C#, you cannot assign a string value to an integer variable
int X = 10;
X = “Hello”; // Compiler error

JavaScript is a dynamically typed language. This means JavaScript data types are converted automatically as needed during script execution. Notice that, in myVariable we are first storing a number and then a string later.
[script] var myVariable = 100;
alert(myVariable);
myVariable = “Assigning a string value”;
alert(myVariable);
[/script]

When a + operator is used with 2 numbers, JavaScripts adds those numbers.
[script] var a = 10;
var b = 20;
var c = a + b;
alert(c);
[/script]

Output : 30

When a + operator is used with 2 strings, JavaScript concatenates those 2 strings
[script] var a = “Hello ”
var b = “JavaScript”;
var c = a + b;
alert(c);
[/script]

Output : Hello JavaScript

When a + operator is used with a string and a number, JavaScript converts the numeric value to a string and performs concatenation.
[script] var a = “Number is : ”
var b = 10;
var c = a + b;
alert(c);
[/script]

Output : Number is 10

[script] var a = “50”
var b = 10;
var c = a + b;
alert(c);
[/script]

Output : 5010

But if you use a minus operator, numeric value is not converted to string
[script] var a = “50”
var b = 10;
var c = a – b;
alert(c);
[/script]

Output : 40

Original source

3d Ocean

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8 Comments

  1. Elena Ep
    July 2, 2017 at 05:47

    @kudvenkat can I ask you something? in 5:50 you place the script before closing the form tag (</form>). But in previous video you said we should place the script before the </body> tag. So it is wrong this way?

  2. Statesman63
    July 2, 2017 at 05:47

    I like your teaching style. I like how you give examples for all of your points. Instead of just saying, "Yes, JavaSript is case sensitive" and moving on to the next point. You give an example of it.

  3. Kyaw Zin Latt
    July 2, 2017 at 05:47

    I would like to write this comment in each and every single videos in each video series.
    YOU ARE A GOOD TEACHER. I am really possessed by your videos. I even forget to sleep by watching your videos. You are really good at explanation. You know categorization and many more. In short, you know how to teach. According to Einstein's quote "If you can't explain it simply, you don't understand it well enough" , you are the one who follow it.
    Please make tutorial videos of MEAN stack on Udemy. I will definitely one of your students. Plus, your course will be one of the bests, I guess.

  4. Vivek Sharma
    July 2, 2017 at 05:47

    Excellent video… great 🙂

  5. shravan kumar
    July 2, 2017 at 05:47

    sir plez upload web-api videos..

  6. naveen murari
    July 2, 2017 at 05:47

    please continue javascript with more speed…

  7. IMGWON
    July 2, 2017 at 05:47

    Great teacher on planet.

  8. Therapyx
    July 2, 2017 at 05:47

    you really have to be a teacher =)
     Btw, will you do some jquery tutorials after JS? Or do you have it in your plans at all?

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