Text and Comments

Text that isn’t processed by the user agent (browser) can be beneficial for a couple of reasons. The first reason is simple documentation, that is, to make your documents more legible and easy to follow should you need to edit them later. The second is to include more information within the document for later access or inclusion by features supported in upcoming browsers.

Comments

HTML comments can be used by the developer of the web pages to document certain sections in the web page. A comment in HTML should be written as follows:

<!–  Your comment here.  –>

Comments are generally used for short text, not for commenting out large sections of HTML code. The text included in the comments is not visible to the user.

CDATA Sections

For larger comment sections, CDATA (character data) sections can be used. CDATA structures are also useful in XML and XHTML. The format for the CDATA tag is as follows:

<![CDATA[   Commented text goes here.  ]]>

Both comments and CDATA tags cannot be nested.

The term CDATA is used about text data that should not be parsed by the XML parser. Characters like “<” and “&” are illegal in XML elements. “<” will generate an error because the parser interprets it as the start of a new element. “&” will generate an error because the parser interprets it as the start of a character entity.

Some text, like JavaScript code, contains a lot of “<” or “&” characters. To avoid errors, script code can be defined as CDATA. Everything inside a CDATA section is ignored by the parser. A CDATA section starts with “<![CDATA[” and ends with “]]>“.

Suryateja Pericherla

Suryateja Pericherla, at present is a Research Scholar (full-time Ph.D.) in the Dept. of Computer Science & Systems Engineering at Andhra University, Visakhapatnam. Previously worked as an Associate Professor in the Dept. of CSE at Vishnu Institute of Technology, India.

He has 11+ years of teaching experience and is an individual researcher whose research interests are Cloud Computing, Internet of Things, Computer Security, Network Security and Blockchain.

He is a member of professional societies like IEEE, ACM, CSI and ISCA. He published several research papers which are indexed by SCIE, WoS, Scopus, Springer and others.