| -- End Ad Box ---> | | | | * Float containment |
| The use of style sheet languages have opened new | | | | * Lack of multiple backgrounds per element |
| possibilities and opportunities for web designers in | | | | * Lack control of Element Shapes |
| terms of freedom in designing and maintainability of | | | | * Lack of Variables |
| web sites. Currently, there are two kinds of style | | | | * Lack of column declaration |
| sheet languages used by many web designers today. | | | | * Cannot explicitly declare new scope independently |
| These are cascading style sheet (CSS) and extensible | | | | of position |
| stylesheet language (XSL). While they are both called | | | | * Poor Layout Controls for Flexible Layouts |
| stylesheet languages, they have very different | | | | EXTENSIBLE STYLESHEET LANGUAGE or XSL |
| purposes and ways of going about their tasks. | | | | XSL has evolved drastically from its initial design into |
| CASCADING STYLE SHEET or CSS | | | | something very different from its original purpose. |
| CSS was designed for the purpose of styling HTML | | | | According to Web design Philippines companies, the |
| and XML, including XHTML document. It uses a | | | | original idea for XSL was to create an XML-based |
| special, non-XML syntax for defining the styling | | | | styling language directed towards paged display |
| information for the various elements of the | | | | media. The mechanism they used to accomplish this |
| document that it styles. As of its version 2.1, CSS | | | | task was to divide the process into two distinct |
| has been considered to be the best style sheet | | | | steps. First, the XML document would be |
| language used for styling documents that are to be | | | | transformed into an intermediate form. The process |
| shown on "screen media". According to Web design | | | | for performing this transformation would be |
| Philippines companies, Screen media is a term used | | | | governed by the XSL stylesheet, as defined by the |
| when a media is displayed as a single page (possibly | | | | XSL specification. The result of this transformation |
| with hyperlinks) that has a fixed horizontal width but | | | | would be an XML document in an intermediate |
| a virtually unlimited vertical height. This works in | | | | language, known as XSL-FO (also defined by the XSL |
| contrast with the term "paged media" which has | | | | specification). |
| multiple pages, each with specific fixed horizontal and | | | | However, in the process of designing the |
| vertical dimensions. Styling paged media involves a | | | | transformation step, it was realized that a generic |
| variety of complexities that screen media does not. | | | | XML transformation language would be useful for |
| Because CSS is designed mainly for screen media, | | | | more than merely creating a presentation of an XML |
| web designers found CSS lacking in terms paged | | | | document. As such, a new working group was split |
| facilitation. But when CSS 3.0 was released, this | | | | off from the XSL working group, and the XSL |
| constraint was lifted by providing new features that | | | | Transformations (XSLT) language became something |
| allowed CSS to more adequately style documents for | | | | that was considered separate from the styling |
| paged display. | | | | information of the XSL-FO document. Even that split |
| Advantages of Using CSS | | | | was expanded when XPath became its own separate |
| Flexibility | | | | specification, though still strongly tied to XSLT. |
| By combining CSS with the functionality of a Content | | | | Advantage Over CSS |
| Management System, a considerable amount of | | | | * The combination of XSLT and XSL-FO creates a |
| flexibility can be programmed into content submission | | | | powerful styling language, though much more |
| forms. This allows a contributor, who may not be | | | | complex than CSS. |
| familiar or able to understand or edit CSS or HTML | | | | * XSLT is a Turing complete language, while CSS is |
| code to select the layout of an article or other page | | | | not; this demonstrates a degree of power and |
| they are submitting on-the-fly, in the same form. | | | | flexibility not found in CSS. |
| Efficiency | | | | * XSLT is capable of creating content, such as |
| A stylesheet will usually be stored in the browser | | | | automatically creating a table of contents just from |
| cache, and can therefore be used on multiple pages | | | | chapters in a book, or removing/selecting content, |
| without being reloaded, increasing download speeds | | | | such as only generating a glossary from a book. |
| and reducing data transfer over a network. | | | | * XSLT version 1.0 with the EXSLT extensions, or |
| Consistency | | | | XSLT version 2.0 is capable of generating multiple |
| When CSS is used effectively, in terms of inheritance | | | | documents as well, such as dividing the chapters in a |
| and "cascading," a global stylesheet can be used to | | | | book into their own individual pages. By contrast, a |
| affect and style elements site-wide. If the situation | | | | CSS can only selectively remove content by not |
| arises that the styling of the elements should need to | | | | displaying it. |
| be changed or adjusted, these changes can be made | | | | * XSL-FO is unlike CSS in that the XSL-FO document |
| easily, simply by editing a few rules in the global | | | | stands alone. CSS modifies a document that attached |
| stylesheet. Before CSS, this sort of maintenance was | | | | to it, while the XSL-FO document contains all of the |
| more difficult, expensive and time-consuming. | | | | content to be presented in a purely presentational |
| Simple Page Editing | | | | format. |
| With a simple change of one line, a different | | | | * For richly specified paged media, such complexity is |
| stylesheet can be used for the same page. This has | | | | ultimately required in order to be able to solve |
| advantages for accessibility, as well as providing the | | | | various typesetting problems which is where XSL-FO |
| ability to tailor a page or site to different target | | | | is used. |
| devices. Furthermore, devices not able to understand | | | | Note: According to Web design Philippines specialist, |
| the styling will still display the content. | | | | XSL-FO does not specify the pages themselves. The |
| Limitation | | | | XSL-FO document must be passed through an |
| Though CSS is a popular style sheet language | | | | XSL-FO processor utility that generates the final |
| currently used today, there are several limitation that | | | | paged media, much like HTML+CSS must pass |
| professional web designers have cited by using pure | | | | through a web browser to be displayed in its |
| CSS web design. These are: | | | | formatted state. |
| * Inconsistent browser support | | | | Disadvantage of XSL |
| * Selectors are unable to ascend | | | | * The complexity of XSL-FO is a problem, largely |
| * One block declaration cannot explicitly inherit from | | | | because implementing an FO processor is very |
| another | | | | difficult. |
| * Vertical control limitations | | | | * CSS implementations in web browsers are still not |
| * Absence of expressions | | | | entirely compatible with one another, and it is much |
| * Lack of orthogonality | | | | simpler than writing an FO processor. |
| * Margin collapsing | | | | |