I am trying to learn html and css, slow but sure. I am using Dreamweaver CS4 as both an editor and to do some things for me. I created a page that has a form on it that stores two fields in a table in a MySQL database. Works fine.

I put the page through the W3C validation service and it had one error, Dreamweaver put inserted POST for the method instead of post (lower case). I changed the case and the form still works as before and now the page has no errors.

My question is: If it worked in all upper case and works in lower case why worry about it? Does it make a difference? Is validation worth the hassle other than knowing the code is correct?

I am interested in learning the whys of validation.

Validation is not, and should not, be the be-all and end-all goal. However, validation is important because it shows errors in your code that could cause problems, unintended results etc. Depending on the doctype you're using, some things are just not valid - such as upper case tags and attributes in XHTML Strict, and other things like <font> tags and the "target=" attribute.

There are some things the validator spews out as warnings that I don't stress over. However, in the pursuit of future-proofing your code, validation is something you should be mindful of. What works today, even if it's 'wrong'.. may not work right 2 years from now.

LNR pretty much covered it all above, but I'll add a little.

What's being validated depends on the doctype you're using. HTML is usually ok with the caps, but xhmtl isn't. HTML will also be fine with the lower case so in general you should always use lower case.

It's been a very long time since I used DreamWeaver, but I think there's a setting somewhere about using xhtml or html when it spits out code. You probably want to set that to xhtml even if you are using html doctypes.

Thank you both for the input.