The savvy reader noticed a distinct lack of absolute in that last statement. The only absolute in automation is that there are no absolutes as Heraclitus would say.
Some theory is in order. We see a website by interacting with its document object model – a complex hierarchical set of objects that represent everything. We greatly simplify this complexity by flattening the hierarchy in various ways into a simple list; the web commands search the list in various ways.
As you have no doubt experienced, websites load progressively – keeping you from getting frustrated since you can begin interacting with content as the rest loads. Our commands can do the exact same thing. For most situations, this behavior is a very good thing, it’s fast and also reliable.
However, most situations are not all situations. Rarely, a given website may have a given element that will progressively load first, but something else (typically some sort of client side code) progressively loads or executes.
Please carefully read and understand what I just wrote. This is situational – element A on page C of website X has this behavior.