One of the latest tools for web design is the XSLT editor. The best way to learn about XSLT is to visit the wonderful web site of the World Wide Web Consortium or the W3 School on the web. The definition of XSLT is eXtensible Stylesheet Language. This language is a stylesheet language for creating XML documents. The function of the XSLT is to transform XML into XHTML. There is a vast knowledge bank available there to learn how to use XSLT for web design. Certification tests and tutorials are available for the earning and learning. If you would like to do some practical applications of this language, there is an on line XSLT editor at the W3 School web site.

The World Wide Web Consortium wanted to provide a language that would be an XML based stylesheet language. The evolution was first XSL and then XSLT, XPath and XSL-FO. With CSS, which is Stylesheets for HTML. Predefined tags are used with HTML and are well understood. With an HTML defined tag each browser knows how it must be displayed. CSS makes displaying special fonts or colors a simple task. The story is different with XSL. XSL is Stylesheets for XML. The opposite is the case with tags for XSL. XSL uses any tag-names with no predefined tag which makes XSL not well understood. When the browser sees XSL tag it will not know how to display it because in HTML the meaning of a tag defines a table but in XSL a tag might mean an HTML table or it could mean something else.

There are more than 100 built in functions in XSLT. Here are some of the functions: - string values - numeric values - date and time comparison - node - QName manipulation - sequence manipulation - Boolean values

There are many more functions with XSLT but these are just some of the notable ones. On your XSLT editor you will notice that the default prefix for the function namespace is fn: When calling a function fn: prefix, such as fn:string(). Another thing to take note of: since fn: is the default prefix of the namespace, the function names, when called, do not need to be prefixed.

The purpose of XSLT is to transform XML documents into XHTML document. XSLT will also transform XML documents to other XML documents. Another language for navigating XML documents is XPath. The most significant part of XSL is when XSLT is recognized by a browser the way HTML and XHTML are, XSLT is used to transform an XML document into another XML document. Here is the big picture of what XSLT can do. The actual mechanism is transformation by XSLT of an XML source tree into an XML result-tree. This is done with an XSLT editor with add/remove elements and attributes to or from the output file. Many other rearrangements can also be done such as sort elements, perform tests and make decisions about which elements to hide and display.