 In this module, I'll talk about JavaScript. JavaScript, if you recall in module number 2, I talked about the skills for in the context of engineering and cloud and the requirement of JavaScript developers was very high. And I promised you at that time that I'll talk about and we'll discuss and we'll actually do development work using JavaScript in this course. So this is the introductory module about JavaScript. JavaScript has many applications but in the context of web-based database applications, usually JavaScript is used at the client side for validation purposes. I have mentioned validation to you a number of times before also in the context of authentication, in the context of checking what goes into the system. So validation in a nutshell briefly means that if I enter the date, I enter the date in the date cell or the text box at my browser instead of entering the name because if the name which is text type goes to the date at the server side, it creates problem for the server. Extra processing or if somebody enters an email address and tries to enter an email address which is not a real email address without an at sign using the JavaScript, I can catch that missing at sign or if somebody enters, if asked to enter official email address and enters a commercial email address or you know what I'm saying so the JavaScript catches this. So we will discussing all of this, you will actually do all of this but before this basics of JavaScript. A brief history of JavaScript. JavaScript was developed and it is was named live script and some marketing guru got an idea of calling it JavaScript and then is confusion people comparing it with Java. JavaScript doesn't have any compiled code. It is an interpreter. There is no binary over it. It runs in your browser and what is the JavaScript program? A JavaScript program consists of literals. It consists of keywords. It consists of operators and anybody who is done programming will find JavaScript fairly easy to program fairly simple to program. It's not complicated and the JavaScript is running in your web page. Your browser is the application domain. It is independent of the server. Almost all the browser support JavaScript. So you can develop limitless applications using JavaScript. So what JavaScript can do? JavaScript can do what I have actually told you what it can do. What it cannot do? There are hardly full-fledged complete applications using JavaScript. You will not find complete application using JavaScript because that is not the purpose or the strength of the JavaScript. What JavaScript can do? What it cannot do is that what was you don't allow it in your browser. It is up to you. What the privileges what you have given to your browser only with respect to those privileges only with respect to those authorities the JavaScript can operate. And then came Windows. Windows elevated JavaScript to the level of visual basic. Before that the JavaScript was not such a mainstream and of course that I have told you. So JavaScript development options. You can develop JavaScript in the ASP.NET environment also. And there are other environments also for developing JavaScript which support which help you understand and code and everything. And of course you can develop JavaScript within your browser and you can see the results within your browser also. And you don't have to configure any environment for JavaScript. There are no specialized servers. There are no specialized client software. There are no specialized middle tier software. So that is the strength of the JavaScript. There is some issue of JavaScript with respect to debugging because that is not very powerful in terms of the browser. So you need to have certain tools such as Firebug for the Firefox browser for the debugging purposes. And there are other tools also available in the market which can help you develop JavaScript applications and debug them effectively efficiently without loss of productivity. And a bit of housekeeping with reference to JavaScript that the JavaScript what is the meaning of white spaces and how it is case sensitive and how the comments are placed and how the things work together. So that is a bit of housekeeping. We will go into the details about it and the JavaScript statements. The JavaScript statement is a collection of as I said before its literals and operators and keywords and they collect and together and the interpreter understands what is there in the JavaScript and acts upon it and generates the results. So this is all happening within the browser. And then we will look at the functions of the JavaScript. There are quite a few functions of JavaScript. I will go into the details in the subsequent sections and then the JavaScript strict mode which is more secure. So that is about it for this module.