When inserting codes into the Blogger template, page element, or blog post, you may have seen error messages that the code could not be parsed, was not well-formed, was broken, or that the elements were not closed properly. These errors can be corrected if you understand the rules that must be adhered to in XHTML documents. Blogger templates use the XHTML 1.0 Strict Document Type. In this article, we shall explain some of the XHTML syntax or rules, so that you may troubleshoot and resolve the problems if these error messages should occur.
XML, HTML and XHTML
We shall keep this short. Just so as you understand what we said about document type, view the Page Source or Source of your Blogger blog. You should see this document type declaration at the very top:-
The terms – XML, HTML and XHTML - refer to the markup language used to write the web pages. Many of us would have heard of HTML (Hypertext Markup Language), invented by Tim Berners-Lee, and used since the early days of internet. XML (Extensible Markup Language) is a meta-language, used to create other markup languages. The traditional HTML was later recast to use the rules of XML and that resulted in a new XML application, called XHTML (Extensible Hypertext Markup Language). Because XHTML rules are strict and unforgiving, not conforming to them when attempting to modify the template would result in error messages. So, what are these rules that Bloggers like us should take note of?
Basic Rules of XHTML
1. Codes to be in lowercase
Since XML is case sensitive, all the element keywords and attribute names used in XHTML should be in the lowercase. For example, the template code is not this:-
If you have noticed, the elements and attribute names between the lesser than (<) and greater than (>) signs have to be in the lowercase. However, the value, which in this case is “Tips for New Bloggers”, can be in the uppercase, lowercase, or mixed case.
2. Attribute values to be in quotation marks
All the attribute values have to be enclosed either in single or double quotation marks. The following examples are not accepted by XHTML:-
Instead, they should be written as such:-