Unobtrusive JavaScript is a general approach to the use of client-side JavaScript in web pages so that if JavaScript features are partially or fully absent in a user's web browser, then the user notices as little as possible any lack of the web page's JavaScript functionality. The term has been used by different technical writers to emphasize different aspects of front-end web development. For some writers, the term has been understood more generally to refer to separation of functionality (the "behavior layer") from a web page's structure/content and presentation, while other writers have used the term more precisely to refer to the use of progressive enhancement to support user agents that lack certain JavaScript functionality and users that have disabled JavaScript. Following the latter definition, unobtrusive JavaScript contributes to web accessibility insofar as it helps ensure that all users—whatever their computing platform—get roughly equal access to all of the web page's information and functionality.