 So students in this module, we'll talk about what JavaScript can do and what JavaScript can do, can and cannot and some very, very brief words about tips on using JavaScript. So let's see what it can do. Before we go into can do and can do, let's have an overview of this module, what JavaScript can do, it cannot be forced on the client, cannot ensure the data security cannot cross domains and so on. So we'll go over the details as we move in the module. Let's see first what JavaScript can do. JavaScript is a complementary language. Complimentary language means that it is a supporting language. It is not a major language in the sense that you cannot develop entire application systems, complex systems using JavaScript. JavaScript supports what you are doing. It complements it, but it is not something entirely on its own on which you can build mega systems. In Ajax, Java is the J. So that is how much popularity or the projection, okay, which Java is getting other than that, JavaScript is an everyday language. It's not like Java, not like C sharp. Okay. Of course, Java tasks can be done at the client side using JavaScript, such as adding interactivity like flash, what kind of interactivity like having dropped on menus. And of course, JavaScript can be used for transforming the text at the client side, okay, adding font colors as per the liking of the client and so on. And the validation also validation means that whatever is supposed to be entered in a certain field, that is validated, for example, if email has to be entered in a field, then it is checked that it is indeed email, it is not the date of birth or something else and so on. So these are the things with JavaScript can do, but what are the things with JavaScript cannot do the JavaScript is limited by the client's browser preferences. It means that whatever if if that it is preference of the client, whether or not even to allow the JavaScript to run at the client end, okay, or maybe the client is using a browser that maybe does not supports JavaScript. It's an old browser, okay, the old browser, okay, or the client has the disabled. So it is a choice of the client, what can happen at the client end, with a JavaScript. It is unlike Java or it is unlike the standard programming languages standard in the sense that you can develop entire complex systems with them, which are not the complimentary languages. It is not platform independent. It is dependent upon the browser in which it is running that we discussed before also. And of course, you cannot guarantee how it's going to behave in one browser as compared to another browser. It is unlike IIS, Internet Information Server or Apache that you develop an application for them and you are guaranteed and you know that how the application is going to work. And if the application fails, for example, in a certain environment on IIS or Apache, you know that it is not going to work in a similar environment elsewhere, but that is not the case for JavaScript. So you cannot guarantee the working of JavaScript elsewhere, unlike Java or other standard languages. So this is one thing with Java cannot do. So you try to understand that the developer has to test the JavaScript in different browser domains, different as browsers. And even then there's no guarantee that it is going to work the same way at other client can't ensure data security. Client is in control, right? It would be rather innocent or naive to believe that the data which is sent over from the client is the same. Because maybe the client has disabled JavaScript and has entered garbage and then submit the data to client and disable client is in control cannot trust the data which is sent by the client to understand this. And therefore you need validation at the server end because the client might be sending malicious data, okay, which will corrupt the server can cross domains, no access to other internet domains or affect them. So if I am running my page at my domain dot com cannot access JavaScript at say Microsoft dot com or other domain dot com. This is a big limitation. Explorer 8 allows some access to data, but that is for Explorer 8. That is limited access. It is not something which is standard in JavaScript, doesn't do servers, right? JavaScript can cannot talk to server or access databases, right? Like the applications which we are developing and discussing as part of this course, JavaScript cannot do all those things, cannot access the database cannot go to the server and make requests. And you need to test JavaScript on different platforms. Okay, if the code does not work on server, you know immediately it's not going to work at others through other people or the clients who access the server, but that is not the case for JavaScript. That is not the case for JavaScript. Some of the tips of using JavaScript follow the standards, do the appropriate technologies at the appropriate time, do the right thing at the right time. So that's all I have for this module. Thank you for your time.