Occasionally it is useful to silently load content into an area on a webpage. For example, you may have a list of recent comments that you want to refresh every minute. Using a meta refresh is one option, but this would cause the whole page to refresh, which could annoy the user. The solution is Ajax, where I’ll reload the content silently without a single page refresh. Even writing the simplist of Ajax functions is quite painful and requires a fair few lines of code to get things done. To make things simpler we’ll use my favourite JavaScript Framework, JQuery.
The plan is to have dynamic content loaded via Ajax and refresh every x seconds. We’ll also have a loading image to show the user something is actually happening behind the scenes, as having nothing while the content is loading could make the user leave. The latter is especially important when querying large sets of data, where a delay is possible. You can get your own loading images from the ajax loading image site.Now we have a plan, we’ll get right into it.
First course of action is to setup our basic html page. It’s nothing amazing, simply a centered divider with a seperate divider for the loading graphic. Here’s the code we’ll be using (for simplicity I’ve used the style tag for the css, as opposed to having a seperate css file: