When to use javascript instead of creating an aspx page?

Question

I am new at C#.Net and i have one question that i couldn't manage to find on the internet. When should i use a classic combination of html + javascript + css instead of using an aspx page with a code behind? As i experienced since i started .net , i found that aspx pages and code behind is a huge ease for developers. I didnt need any piece of javascript code since i started. There must be something wrong. I think i am missing a point. Can you answer my question and tell me some examples that i must use html+javascript+css instead of aspx + aspx.cs or vice versa?? Have a nice day.

Answer 1

Points you are missing

• Code behind is not what makes ASP.NET; you can make a web app with all C# code right into the aspx files.
• If you choose ASP.NET and C# for a web app, all your pages should be aspx ones, except for very specific and not very common situations.
• You need to understand the difference between server side scripting and client side scripting. ASP.NET is a server side scripting technology while javascript is a client side only one. Take a look.
• You can create aspx pages that are as simple as you want -even without any relevant serverside scripting- and thats all right.

Attempt to answer

You use the word must, so:

• You must use aspx instead of only javascript if you want any kind of server side processing.
• You must use an html file with plain javascript, jquery and css if there is the specific requeriment to do so, wich would be very uncommon. That could be a situation where a) the page should be as fast as it can possible be b) you don't mind everyone to be able to see your full code by just selecting view source on the browser c) there is no need at all for server side processing d) you don't mind about the little extra mix of technologies on your web application.

Answer 2

Javascript is a client side technology, running only in the browser, whereas ASP.NET runs on the server side. These allow you to achieve different and complementary things.

With a classic server side language, any user interaction that you want to respond to must typically be posted across the internet from the browser to your server. It is then processed by the server, which responds with a new page for the browser to load. This generally means that the response time for the user is slower, though you will have access to a much richer programming environment on the server.

With a client side language, everything is processed on the browser. This allows for faster feedback to the user, though at the expense of working within the much more restricted programming environment that the browser gives you, and with no access to stuff your application may depend on, such as your database.

Of course, the lines are blurred somewhat when you make an AJAX request (usually a call written in Javascript that makes a request to the server, receives the response, and updates the page dynamically).

You mention that you have not used any Javascript so far. Perhaps as a starting point you'd like to investigate validating user input on the client side? This way, errors are caught and reported to the user immediately without the cost of the round trip to the server. http://www.tizag.com/javascriptT/javascriptform.php

Both client side and server side technologies can be powerful and useful. Use a combination of them both to give the best experience for the user.

Answer 3

If you are looking for highly customizable and high performance pages, then I would go with html + javascript + css and make calls to some webservice. This way you are not restricted by asp.net controls. Also, there are a lot of caveats with standard out of the box web forms that can lead to page performance issues and overhead - ViewState being one. You can also design your own asp.net controls as well, but there is some learning curve.

It really boils down to personal preference (there isn't anything in one that you can't do in the other) : Fundamentals vs Abstraction. To me javascript has always felt somewhat cumbersome when used in conjunction with webforms, however, with mvc it is a lot more natural, as it would be with a standard html + javascript + css page.

Answer 4

When you want to create static pages you can use html+css+javascript instead aspx. In case you want things more dynamic you have to use aspx with cs.

For more info go http://www.w3schools.com/aspnet/aspnet_pages.asp

Answer 5

You use Javascript/JQuery to perform operations that does not need any server side processing like validating controls for a range or for empty values, some fancy UI stuff. It is much faster than the code behind because it does not post back to server however you could use UpdatePanel aspx server control to have partial post back and avoid reloading the page.

As a web developer you should always use combination of server-side processing and client-side processing. Working logic and application processes on the client-side allows browser based applications to seem more responsive and to have more "snappiness" to them.

Answer 6

In my experience, using Javascript/jQuery in .NET has been for UI and client-side validation purposes. If you are building an app that does not require Javascript to meet your client's requirements, then take advantage of what .NET has to offer. However, implementing Javascript is not that hard, so feel free to use what you prefer and is in the best interest of the client. You can still write and use Javascript in an ASPX page.

Answer 7

from my experience the main aim to use the companion of html,css,javascript with asp.net when the client needs is for a web app that acts exactly like win app

that u don't need to flush over the page to the server and come back again

Answer 8

One of your considerations might well be speed. Javascript in a web-page will run on a site visitor's browser. Code-behind runs on the server hosting the page.