Preview

Preview is where output of a particular document, page, film, etc. is displayed before it is produced in its final output form. It is most often used in the theatre and cinema, where performances of a film, play or musical may take place before the official opening night, usually for the benefit of critics.

In a computer, one may choose to preview a page of text on screen before printing it. This is known as print preview.

Many websites and online forums allow users to preview their content before submitting it. This is especially important in sites with complex markup, but also serves as second chance to catch spelling errors and similar issues.