Ajax has become common place in almost all websites. Users get a faster web experience, at the cost of a slight bit of complexity to the developer. But it's the users who make the site and not the other way around, so it's totally a good route to take at times. There's tons of different ways to make AJAX requests in ASP.NET, and I'll be covering just one of them here today. It's probably one of the fastest ways to do it, and great if you're in a bit of a time crunch or new to this whole AJAX world. This post will assume that you already know the basics about AJAX, so I'll skip the preliminaries and get right to the fun stuff. I'm using Visual Studio 2013 for all of the screenshots and examples. I created a default test project so everything is right out of the box.
Here's a quick AJAX FileUpload written for ASP.NET WebForms that I use every now and then using the old tried and true method of an iframe.