At this stage, our site would be optimized and tested for performance, but what about compatibility?
Although a wide range of available browsers have remained relatively static (at least for the ones in mainstream use), the functionality they offer is constantly changing; this makes it difficult for developers and designers to handle all of the nuances required to support each browser.
In addition, the wide range makes it costly to support. In an ideal world, we would support every device available, but this is impossible; instead, we must use analytical software to determine which devices are being used for our site and therefore worthy of support.
If we test our site on a device such as an iPhone ...