 Hello everyone, myself is Supriya Ambarkar from Walton Institute of Technology, Solaapur. Today we are going to discuss a topic on JavaScript introduction. The learning outcome of this session, the students will be able to learn basic concepts of the JavaScript as well as students will be able to learn how to embed a JavaScript in HTML. Now we will see the introduction part of JavaScript. JavaScript is a scripting language which is also known as a lightweight interpreted programming language. JavaScript was first known as LiveScript. Later, NetScap changed its name to the JavaScript. JavaScript made its first appearance in NetScap 2.0 version in 1995 with the name LiveScript. The ECMA 262 specification defined a standard version of the core JavaScript language. The general purpose core of the language has been embedded in the NetScap, Internet Explorer and other web browsers. JavaScript is usually embedded directly into HTML pages and JavaScript was designed to add interactivity to the HTML pages. So this is all about the introduction part. Now we will see the different types of JavaScripts which are available. So basically there are the two different types. First one is a client-side JavaScript. The examples are the AngularJS. Then the server-side JavaScript that is an example NodeJS. Now we will see why study JavaScript. The JavaScript is one of the three languages for the web development so that all web developers must learn HTML, CSS and JavaScripts. So HTML is an extension of a hypertext markup language to define the contents of the web pages to be seen in the website. Then CSS means cascading style sheets which specify the layout of web pages. Then finally the JavaScript is there to program the behavior of the web pages. So it's having the importance of studying the JavaScript. Now we will see JavaScript versus Java, whether it is similar or it's having some differences. So Java and JavaScript are two completely different languages in both the concepts and design also. Java developed by the Sun Microsystems which is a powerful and much more complex programming language. JavaScript has more relaxed syntax and rules like fewer and looser data types are there. Variables don't need to be declared all the times. Then errors often silence are in the JavaScript. Few exceptions are there. In JavaScript key construct is a function rather than the class. The JavaScript contained within a web page and integrates with its HTML or CSS contents. So this is a famous Hello World program. Today we are going to see here HTML tag, inside that body tag, then script tag. And script tag we have introduced the different attributes like a language and type. And we have called one of the methods that is document.write function which returns the string Hello World. So this is the program we will discuss in detail. JavaScript can be implemented using JavaScript statements that are replaced within the start and end script HTML tags in the web page. The script tag is an extension to the HTML that can enclose any number of JavaScript statements. You can place the script tags containing your JavaScript anywhere within your web page. But it is normally recommended that you should keep it within the head tag or within a body tag. The script tag alerts the browser program to start interpreting all the text between these tags as a script. The script tag has two important attributes such as language and type. The language specifying what scripting language you are using. That means JavaScript. And type specifying to indicate the scripting language in use and its value should be set to the text slash JavaScript. Here we call a function document.write and which writes a string into our HTML document. So the output of this program is a Hello World. So this is a famous Hello World program. Now we will discuss the JavaScript variables. Variables are used for storing data. It is one kind of a container. For information which you want to store, a variable's value can change during the script. The rules for variable names are such as it should be declared with the var where keyword. The names of the variables are the case sensitives. So you should be must begin with a later with the underscore character and so on. Then upper cases and lower cases should not be same. So it's having a difference. So case sensitivity is there. The types are not specified, but JavaScript does have the types at loosely coupled. So there are the different types are automatically converted. Number, Boolean, string array, object, functional, undefined and so on. So we can find out a variable's type by calling a type of that particular function and you will be getting the particular data type of that variable. Now we will see how to embed a JavaScript in HTML. First, by using the script tag. After the HTML tag, we are able to suppose to insert the script tag. Second, by specifying a file of JavaScript code, so which having an extension.js. Third, by specifying a JavaScript expression as a value for the HTML attribute. So we can specifically give the attribute value. And last, by using the event handlers within a certain other HTML tags. So in such a way, we are able to suppose to embed a JavaScript in HTML. Now we will see the script tag, what it will be happen. It will be work on the HTML page. So script tag here, the JS code can be placed directly in the HTML files body or head tag. Like a CSS. So for example, script, then language is equal to JavaScript and the type will be the text slash JavaScript. And we have to call the function, document dot write, hello world should be there. And the end tag with that particular script. So here directly, you are able to suppose to place in a HTML file. Second is we can link the JavaScript file with an extension.js. So with the help of the input of that particular script tag, SRC, we can specify a particular name of a file.js. And accordingly, the externally we are able to suppose to call that JS file inside of HTML. So this is all about linking and how the exactly script tag is going to work. So JavaScript basics are there. It defines the variables. It having AFL statements, switch cases. So many operators are there, pop up boxes, alert boxes. So many functions are available readily. We are having a loops category like a for loop, while loop. Different events we are going to call. Try catch block throws the particular exceptions. Spatial text are there, guidelines. So these are the some kind of a feature. It's having a basic features of the JavaScripts. We are able to suppose to handle. Now pause the video and write down your answer. Do you have to specify the data type of a variable when you declare it in JavaScript? The answer is JavaScript is a loosely typed language. So that means you do not have to specify the data type of a variable. When you declare it because data types are converted automatically, as needed during the script executions. So for example, if you define a particular variable ABC as follows, like a var variable ABC, it's having an value like a 22. And later, if you wish to define that particular variable as a string. So you could assign that same variable ABC name for the string value. Like ABC is equal to hello world. So inside a particular quotation, you are able to suppose to declare that. So this is all about the particular data type. Now we will see the different data type convergence. In the expressions here involves the numeric and string values. JavaScript converts the numeric values to the strings. Here the following statements are there, x and y statements. So the addition of two numbers is a string, 22 is a numeric. Here the 22 is a numeric is the addition of two numbers are the string. So automatically the conversion of numeric values to the strings will be happened. Now the function part, how to define and call the function. Functions are a collection of JavaScript statement that perform a specified task. Functions are used whenever it is necessary to repeat an operations. Functions are one of the fundamental building blocks in the JavaScript. A function is a JavaScript procedure. Function defines the basic parts. It's having a keyword function. It's having a name. It should be comma separated list of arguments to the function in a parenthesis. Then the statement in the function enclose in a curly braces. So this is an function example. Here the name of the function we have defined is a square. There is an arguments. It returns the particular number star number. Means it returns the square of that particular number. So inside that particular tag, head tag, we have defined the function. And inside the body tag, we have called that particular function. Document.write the function return the square of a five. So the output is the function return 25. This is an output regarding this particular function example. The other tags are there in terms of the HTML, head tag, then the slash body tag, HTML tag. Everything is there. So we have called the script tag inside the head and body tag. So these are the few references which I have referred for this particular topic. Thank you one and all. Thank you.