Tuesday 07th of February 2012 05:23:54 AM

Style Guide

CSS Style Sheets & Tips

Library projects must use valid Cascading Style Sheets (CSS) to control typography, color, and other layout elements. Style Sheets must be linked in a way that accommodates the capabilities of new and old browsers.

When you create your data using an XML editor (that you can write), you can not only input the content of your data, but also define the structural relationships that exist inside your data. By allowing you to define your own tags and create the proper structural relationships in your information (with a DTD), you can use any XML parser to check the validity and integrity of the data stored in your XML documents. This makes it very easy to validate the structure and content of your information when you use XML. Without XML, you could also provide this validation feature at the expense of developing the code to this yourself. XML is a great time saver because most of the features that are available in XML are used by most programmers when working on most projects.

By using XML and Java, you can quickly create and use information that is properly structured and valid. By using (or creating) DTDs and storing your information in XML documents, you have a cross-platform and language independent data validation mechanism (for free) in all your projects!

You might use XML to define file formats to store information that is generated and used by your applications. This is another use of the structured nature of XML. The only limitation is that binary information can't be embedded in the body of XML documents. For example, if you wrote a word processor in Java, you might choose to save your word processor documents to an XML (actually your ApplicationML) file. If you use a DTD then your word processor would also get input file format validation as a feature for free. There are many other advantages to using XML and a file storage format for your applications which will be illustrated later in the chapter.

Here are some benefits of the structured nature of XML:

A number of valid Style Sheets have been provided for your use. If you wish to create your own Style Sheets, please discuss your requirements with the Branch Library's Web Coordinator.

So, with the background repeating, we can see from Figure 6-48 that the tiling pattern starts with the position specified by background-position. This first image is known as the origin image , and it's very important to understanding the next section.

Figure 6-48

Figure 6-48. Use of the background-position property sets the origin of the tiling pattern

As it happens, the positioning of backgrounds does contradict something I said earlier. background-position is the only background property with restrictions, as it may only bespecify any color in the 8-bit color spectrum, not just sixteen (or however many) named colors. This is accomplished by taking advantage of the way colors are generated by computers.

3.1.2. Colors by RGB

Computers create colors by combining different levels of red, green, and blue,may already have defined such styles. Assume that a UA has the following styles defined: 

UL {list-style-type: disc;}
UL UL {list-style-type: circle;}
UL UL UL {list-style-type: square;}

If this is so, and it's likely that it will be, you will have to declare your own styles to overcome the UA's styles. Inheritance won't be enough in such a case.

Be careful about specifying fonts in the <BASEFONT> or <FONT> tag.  You can count on all browsers having the basic fonts--Arial, Courier and Times Roman--but browsers that don't have the font you specify will simply substitute some other font, and the effect you want may be diminished or lost.  The <BASEFONT> or <FONT> tags can list multiple fonts in order of preference.  The list should include a generic font family as a last resort, e.g.
   <FONT FACE="Creepy, Times New Roman, serif">
Generic font families include serif, sans-serif, monospace, cursive