In some of the books I've read involving time travel, women wearing short skirts and so on are seen as scandalous; sometimes they're mistaken for prostitutes. However, I'm aware that fashion trends have waxed and waned over the centuries. Did western women of any region and era wear bare legs as a style of fashion?
Hemlines raise and lower constantly, but stockings are always worn. In the later half of the 18th century the fashionable length was anywhere from 3-8" off the ground. When in working attire it could be mid-calf. The popular length goes down to ankle length as the century turns, but raises up now and then such as this French fashion print from 1815. It isn't until the middle of the 19th century that you loose the view of the ankles.
The important thing to note is that it's not prostitutes that wear shorter skirts, it's working women. Laundresses for example, will often remove their shoes, if not their stockings, as well as wear shorter hems to avoid dampness.
Some Georgian/Regency dresses might show a little bit of ankle (example), but for the most part it has never been part of western high fashion until the 20th century.
There are many traditional European folk costumes with knee-length or ankle-length skirts though, for example Transylvania, Poland (woman is on the left), Switzerland, etc. However note that almost all women still wore thick stockings or boots to cover their legs, no one seem to go completely bare-legged (excluding the likelyhood that some very poor women could not afford stockings and shoes.)
