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Web Design References

Web Design Glossary

P

Padding
In CSS padding is a property that allows the author to specify how much space will be inserted between the element border and the element content. Negative values are not allowed.
Paper Prototype
A paper prototype is a paper sketch of an interface with just enough detail to make design decisions and usability evaluations relating to the function and flow of the interface, not the look.
Persistent Style Sheet
A persistent style sheet is a style sheet that is always applied to the document. One example is the user agent's style sheet: it is always applied, although you can override it with your own styles.
PHP
PHP is an acronym for PHP hypertext Preprocessor. It is a server side scripting language for creating dynamic web pages. This means that it works within an HTML document to confer to it the capacity of generating content on demand. You can convert your site into a web application, not just a collection of static pages. A Web server processes PHP script. After the server plays with the PHP code, it returns plain old HTML back to the browser. This kind of interaction allows for complex operations.
Pixel
The word "pixel" is derived from "picture element". In graphics, it refers to smallest resolvable rectangular area of an image. It is how monitors divide the display screen into thousands or millions of individual dots. In CSS a pixel is a relative unit of measure dependent on the viewing device. Pixel units are relative to monitor resolution in contrast to the percent or em units that are relative to a browser setting. Percent and ems are considered best practice for accessibility.
Pixels Per Inch (PPI)
Pixels Per Inch (PPI) is the resolution of an image file. Web graphics and screenshots are made up of dots called pixels. PPI is also the horizontal and/or vertical density of an operating system's graphical display, from the point of view of the operating system (and in turn, of the applications and images running on it).
Plugin
A plugin is a module (either hardware or software) that adds a special feature to a larger system or program. For more information consult: Plugins, PDF, PowerPoint, etc.
Pluralistic Walkthrough
Pluralistic walkthroughs are when groups of users, developers, and usability experts walk through a task scenario. Group walkthroughs have the advantage of providing a diverse range of skills and perspectives to bear on usability problems. As with any inspection the more people looking for problems, the higher the probability of finding problems. Also, the interaction between the team during the walkthrough helps to resolve usability issues faster.
Portable Document Format (PDF)
PDF is a file format developed by Adobe Systems Inc., as a way to publish documents electronically, with good formatting for printing, and document security (documents are generally read only). Originally it was in an image format. It was conceived as a way to make Adobe's Postscript printer language portable, and it mostly developed along the lines of press printing document production. Its prevalence can be attributed to the ease with which one can create PDF files. PDF has accessibility and usability issues. One of the main problems with PDF concerns accessibility issues associated with the document format, but this is only part of the problem. Even when users have the technology required to access information presented in this format, there can be content elements which have not received appropriate treatment to support accessibility such as using structural formatting for headings, etc. or text equivalents for images. Compared to HTML, PDF is slow and cumbersome. Many applications can save to formats other than their native file format, such as HTML, so this option when available is preferable to PDF, even when it needs to be cleaned up for the web. For more information consult Plugins, PDF, PowerPoint, etc. and PDF Usability.
Portable Network Graphics format (PNG)
PNG is an image format was developed as the successor to the GIF format. It has a more efficient compression algorithm than GIF.
Preferred Style Sheet
These style sheets are enabled by default. They are "on" when the page is loaded. They can then be disabled if the user selects an alternate style sheet. To make a style sheet preferred, the rel attribute is set to "stylesheet" and the style sheet is named with the title attribute.
Presentational Markup
Presentational markup directly describes the way content should be displayed, rather than its structure or semantics. It is markup used to control the visual appearance of a web page. In contrast structural markup is used to provide a logical meaning and structure to a document. Presentation markup is meaningless outside of a visual medium. The use of presentation markup is strongly discouraged. It is generally considered best to separate structural markup from presentation markup. In fact, if you are in doubt as to whether a certain piece of markup is structural or presentational, a good test is to ask, "how might that be rendered in voice".
Primary Navigation
Primary navigation is the general menu choices that are repeated on most (if not all) of the pages contained in the site. It is sometimes called the main menu. Primary navigation is sometimes referred to as global navigation or functional navigation. Primary navigation bars provide shortcuts to main sections on a website.
Print Disabled
George Kerscher invented the phrase "print disabled" to describe people who could not access print. It refers to a person who cannot effectively read print because of a visual, physical, perceptual, developmental, cognitive, or learning disability. The Google Library Project Settlement defines "print disabled" as a "User is unable to read standard printed material due to blindness, visual disability, physical limitations, organic dysfunction or dyslexia."
Programmatic Determinable
"Programmatic Determinable" means that a specific value can be determined in a standard, machine or software readable form. Assistive technology does not have to guess about it, or use heuristics. It is authoritative, precise, and provides unambiguous specificity. It allows software, including assistive technology, to extract and present the information in different modalities.
Progressive Enhancement
Progressive enhancement is a web design strategy, which is the opposite of graceful degradation. A basic markup document is created, geared towards the lowest common denominator of browser software functionality, and then the designer adds enhancements to the presentation and behavior of the page, using modern technologies like Cascading Style Sheets or JavaScript. For more information consult Progressive Enhancement.
Property
In CSS a property is named style attribute or parameter for a markup element specified in a style sheet declaration, e.g. color, background, font-family, padding etc., that is assigned a certain value. Properties are always followed by a colon to separate them from their value pair. A declaration contains one or more properties the individual pieces of style to be applied to the selected element.
Prototype
A prototype is a partially completed mockup of your final website. Prototyping allows you to test certain parts of the final website, especially when it is incomplete. With many sites, this model can be as simple as paper-and-pencil drawings or as complex as actual working code. For more information consult Prototyping.
Pseudo-Class
In CSS, a pseudo-class is way of selecting certain parts of a HTML document based in principle not on the HTML document tree itself and its elements or on characteristics like name, attributes or contents, but on other phantom conditions like language encoding or the dynamic state of an element. The original pseudo-class defined dynamic states of an element that are entered and exited over time, or through user intervention. CSS2 expanded on this concept to include virtual conceptual document components or inferred portions of the document tree e.g. first-child. Pseudo-classes operate as if phantom classes were added to various elements.
Pseudo-Element
In CSS, pseudo-elements are used to address sub-parts of elements. They allow you to set style on a part of an element's content beyond what is specified in the documents. In other words they allow logical elements to be defined which are not actually in the document element tree. Logical elements allow implied semantic structure to be addressed in CSS selectors.