What is DDT?

**fred** · 02-17-2010, 06:23 AM

I Really Want To Know What is meant by DDT in Web Development?
Kindly Guide Me.

**kschweick** · 02-22-2010, 02:07 PM

I can't actually think of anything related to web design that is abbreviated DDT... perhaps you meant DTD?

DTD stands for document type definition. It should be the very first line of code in an HTML file specifying exactly which version of HTML you are using. For example, there is HTML and XHTML and both have version numbers (like HTML 4.01 and XHTML 1.0). Then you can also specify whether you are coding in strict, transitional, or frameset; where strict code should technically not use any depreciated elements, transitional may include transitional elements, and frameset should be used if you have frames on your site and I think it also supports depreciated elements but I'm not sure (my tip is just don't use frames for many reasons).

Anyway, you can look these up on the W3C's website, but here are two common examples:

EDIT: I apparently still don't have enough posts to use URLs yet, so my examples below didn't quite work. Anywhere you see H T T P in my example, you need to replace that with http colon slash slash.

HTML 4.01 transitional - for sites using HTML (not XHTML) and that make use of depreciated tags (elements from an older version of HTML that were retired in 4.01)

HTML Code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "H T T P w3.org/TR/html4/loose.dtd">

XHTML 1.0 strict - for sites with XHTML that don't use any old tags

HTML Code:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "H T T P w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

Notice that on the XHTML example, you don't end this with a /> because it is not exactly an HTML tag.

Hopefully that's what you meant, but if not, maybe you could explain in more detail in what context the abbreviation was used?