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:

Here is my Web Page with a background image!

Friday 21st of November 2008 06:36:51 PM

Default

none

Inherited

no

Applies to

all elements

colorIE4 Y/Y IE5 Y/Y NN4 Y/Y Op3 Y/-

Sets the foreground color of a given element. For text, this sets the text

This happens quite often, as a matter of fact, and was discussed in the previous chapter. Take the example of a short document, composed of no more than a few paragraphs and H3 elements, where the first paragraph contains a floated image. Further, this floated image has a right margin of 5 pixels (5px ). You would expect the document to be rendered very much as shown in Figure 8-39.



Figure 8-39. Expected floating behavior

Nothing unusual there, of course, but Figure 8-40The other browsers don't allow negative padding lengths.

7.5.1. Percentage Values and Padding

As stated earlier, it's possible to set percentage values for the padding of an element. Percentages are computed in relation to the width of the parent element, so they can change if the parent element's width changes in some way. For

Opera 3.5 allows negative padding values, but this was fixed in Opera 3.6. The other browsers don't allow negative padding lengths.

7.5.1. Percentage Values and Padding

As stated earlier, it's possible to set percentage values for the padding of an element. Percentages are value prevents coexistence with floated elements on both sides of theelement, as shown in Figure 7-76:

H2 {clear: both;}



Figure 7-76. Clear on both sides

If, on the other hand, we're only worried about H2 elements flowing past floated elements to their right, then we'd use H2 {clear: right;}, with the result shown in Figure 7-77.



Figure 7-77. Clear to the right

Finally, there's clear:none, which allows elements to float to eitherside of an element. As with float: