Information on the Wikipedia preview function is at Help:Show preview

In computing, a preview may be where output of a particular document, page, film, etc. is displayed before it is produced in its final form. In the case of printed material this is known as a print preview. Memory (Random Access Memory) Look up computing in Wiktionary, the free dictionary. ...

Many websites and online forums allow users to preview their content before submitting it. This is especially important in sites with complex markup (not WYSIWYG), where it serves as second chance to catch spelling errors and similar issues. WYSIWYG (IPA Pronunciation [] or []), is an acronym for What You See Is What You Get, used in computing to describe a system in which content during editing appears very similar to the final product. ...

In performing arts, a preview can be a performances of a film, play or musical that may take place before the official opening night, usually for the benefit of critics. A preview or a "teaser" is also is used build hype for a film, play or musical to attract a larger audience.(see also: vernissage) The performing arts are those forms of art which differ from the plastic arts insofar as the former uses the artists own body, face and presence as a medium, and the latter uses materials such as clay, metal or paint which can be molded or transformed to create some... A vernissage (varnishing, from French), also known as a preview or private view, is the ceremonial start of an art exhibition. ...