Editing Cross-platform software (section)

==== Design <span class="anchor" id="Design strategies"></span> ====
Because of the competing interests of compatibility and functionality, numerous design strategies have emerged.

Many software systems use a layered architecture where platform-dependent code is restricted to the upper- and lowermost layers.

=====Graceful degradation=====
Graceful degradation attempts to provide the same or similar functionality to all users and platforms, while diminishing that functionality to a least common denominator for more limited client browsers. For example, a user attempting to use a limited-feature browser to access Gmail may notice that Gmail switches to basic mode, with reduced functionality but still of use.

=====Multiple codebases=====
Some software is maintained in distinct codebases for different (hardware and OS) platforms, with equivalent functionality. This requires more effort to maintain the code, but can be worthwhile where the amount of platform-specific code is high.

=====Single codebase=====
This strategy relies on having one codebase that may be compiled to multiple platform-specific formats. One technique is [[conditional compilation]]. With this technique, code that is common to all platforms is not repeated. Blocks of code that are only relevant to certain platforms are made conditional, so that they are only [[interpreter (computer science)|interpreted]] or [[compiler|compiled]] when needed. Another technique is separation of functionality, which disables functionality not supported by browsers or OSs, while still delivering a complete application to the user. (See also: [[Separation of concerns]].) This technique is used in web development where interpreted code (as in scripting languages) can query the platform it is running on to execute different blocks conditionally.<ref>{{cite journal|last=Corti|first=Sascha P.|title=Browser and Feature Detection|journal=MSDN Magazine|date=October 2011|url=http://msdn.microsoft.com/en-us/magazine/hh475813.aspx|access-date=28 January 2014}}</ref>

=====Third-party libraries=====
Third-party libraries attempt to simplify cross-platform capability by hiding the complexities of client differentiation behind a single, unified API, at the expense of [[vendor lock-in]].

=====Responsive web design=====
[[Responsive web design]] (RWD) is a Web design approach aimed at crafting the visual layout of sites to provide an optimal viewing experience—easy reading and navigation with a minimum of resizing, panning, and scrolling—across a wide range of devices, from mobile phones to desktop computer monitors. Little or no platform-specific code is used with this technique.