paper documents relatively closely, but computers can also add multimedia animation, and interactivity. Page layout for interactive media overlaps with interface design and user experience design; an interactive "page" is better known as a graphical user interface (GUI). Modern web pages are typically produced using HTML for content and general structure, cascading style sheets to control presentation details such as typography and spacing, and JavaScript for interactivity. Since these languages are all text-based, this work can be done in a text editor, or a special HTML editor which may have WYSIWYG features or other aids. Additional technologies such as Macromedia Flash may be used for multimedia content. Web developers are responsible for actually creating a finished document using these technologies, but a separate web designer may be responsible for establishing the layout. A given web designer might be a fluent web developer as well, or may merely be familiar with the general capabilities of the technologies and merely visualize the desired result for the development team. Projected pages Projected slides used in presentations or entertainment often have similar layout considerations to printed pages. The magic lantern and opaque projector were used during lectures in the 1800s, using printed, typed, photographed, or hand-drawn originals. Two sets of photographic film (one negative and one positive) or one reversal film can be used to create positive images that can be projected with light passing through. Intertitles were used extensively in the earliest motion pictures when sound was not available; they are still used occasionally in addition to the ubiquitous vanity cards and credits. It became popular to use transparent film for presentations (with opaque text and images) using overhead projectors in the 1940s, and slide projectors in the 1950s. Transparencies for overhead projectors could be printed by some photocopiers. Computer presentation programs became available in the 1980s, making it possible to layout a presentation digitally. Computer-developed presentations could be printed to a transparency with some laser printers, transferred to slides, or projected directly using LCD overhead projectors. Modern presentations are often displayed digitally using a video projector, computer monitor, or large-screen television. Laying out a presentation presents slightly different challenges than a print document, especially because a person will typically be speaking and referring to the projected pages. Consideration might be given to: Editing the information presented so it either repeats what the speaker is saying (so the audience can pay attention to