Client-side scripting: Difference between revisions

Revision as of 06:10, 1 February 2006

Revision as of 19:01, 5 May 2007

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'''Client-side scripting''' generally refers to the class of [[computer program]]s on the [[World Wide Web|web]] that are [[Execution (computers)|executed]] ''[[client-side]]'', by the user's [[web browser]], instead of ''[[server-side]]'' (on the [[web server]]). This type of [[computer programming]] is an important part of the [[Dynamic HTML]] (DHTML) concept, enabling [[web page]]s to be [[Script (computer programming)|scripted]]; that is, to have different and changing content depending on user [[input]], environmental conditions (such as the time of day), or other variables.

Web authors write [[client-side]] scripts in languages such as [[JavaScript]] ([[Client-side JavaScript]]) or [[VBScript]], which areis based on several standards:

*[[HTML scripting]]

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By viewing the file that contains the script, users may be able to see its [[source code]]. Many web authors learn how to write client-side scripts partly by examining the source code for other authors' scripts.

In contrast, [[server-side scripting|server-side scripts]], written in languages such as [[Perl]], [[PHP]], and [[PHPVBScript]], are executed by the web server when the user requests a document. They produce output in a format understandable by web browsers (usually HTML), which is then sent to the user's computer. The user cannot see the script's source code (unless the author publishes the code separately), and may not even be aware that a script was executed. The documents produced by server-side scripts may, of course, contain client-side scripts.

Client-side scripts have greater access to the information and functions available on the user's computer, whereas server-side scripts have greater access to the information and functions available on the server. Server-side scripts require that their language's [[Interpreter (computing)|interpreter]] is installed on the server, and produce the same output regardless of the client's browser, [[operating system]], or other system details. Client-side scripts do not require additional software on the server (making them popular with authors who lack administrative access to their servers); however, they do require that the user's web browser understands the scripting language in which they are written. It is therefore impractical for an author to write scripts in a language that is not supported by the web browsers used by a majority of his or her audience.