Script writing or, more commonly, scriptwriting can be broadly defined as writing the dialogue and relevant directions for a production. As scripts are used for a variety of purposes in a number of settings, there are specific criteria or formal structures that are often unique to a given type of script. For example, a screenplay for a film might include camera specific terminology---such as pan, zoom or deep focus---that would not appear in the script for a play.
Screenplays
Screenplays are scripts written specifically to be produced for a visual medium, such as film or television. For the most part, screenplays are fictional in nature and designed to tell a story. Screenplays typically include a variety of information including setting, dialogue, camera instructions and may include editing instructions. It should be noted that most screenplays are not produced as written. The director, production crew and even the actors may all directly or indirectly alter the script during production, reports Screenwriting.info.
Playwriting
Plays are productions that occur live, on a physical stage rather than the metaphoric stage of film or television. Like a screenplay, a play script includes dialogue and directions. According to Script Frenzy, a play script will include stage and scene instructions, as well as provide character names and descriptions.
Audio Drama
Scripts for audio dramas share a number of components with screenplays and the scripts for stage plays, often sharing terminology. There tends to much more extensive use of the so-called narrator to provide third person perspective than in other fictional scripts. The dialogue is also different in that it includes more descriptive language about the surroundings to help establish setting, reports crazy Dog Audio Theatre. Instructions lean toward the necessary audio components that need to accompany a given scene and may also give direction to the voice actor about how a line should be delivered.
News Scripts
While appearing natural on screen, most news anchors are provided with scripts to read via teleprompters. News scripts tend to be bare-bones affairs that provide informational content. The components of the script the anchors do not read aloud generally include directions for the production staff about when to run a clip or to cut to a live anchor in the field.
Other Scriptwriting
Other types of scriptwriting include producing story/dialogue for video games, education films, online content such as podcasts or marketing materials and even commercials. These scripts tend to follow the same general patterns as plays, audio dramas and screenplays.