According to best practices, page objects should be shown as they load, giving a perception of fasting loading pages, while not rendering pages unusable in the case a component fails to load. This lets the user access the page faster and skip loading resources should they navigate away. However, in the case a throbber is unavoidable, consistent styles should be applied as follows.

throbber_circle.gif

Asynchronous calls should be shown using the circular loading throbber while disabling only certain parts of the page relevant to the on-going process.

loading.html

Only in the rare case that components require a fully loaded page, should the modal throbber be used.