When you load some data with ajax, you will probably want to show the users in some way, that data is loading. To show the text “loading…” would be enough. Another, very common way to do it to show a spinner, a rotating image. In sharepoint we can use the built-in gif which can be found in /_layouts/images/loading16.gif. Well, it is actually not so good, because this image is not so beautiful. A better way is to create your own gif image which is exactly suited for our needs. Or even better: don’t use any images. Use the light-weight javascript library called spin.js for creating spinners. It is fully customizable, compatible with older browsers. You can customize it interactively on the spin.js homepage.