Realizing I'm Outdated. Love at 2nd "site" towards HTML5

I have been hearing about HTML5 for about a year now but I haven't paid too much attention cause coding with it means browser compatibility issues.

However, I came across a code on a form of mailchimp newsletter. I saw some attributes and attribute values that are new to my eyes. placeholder and required attributes, and the "email" input type.

At first I thought they are just used for the signup form's javascript, I assigned my teammate to make the jquery validate for it. but a minute later I was surprised by my browser pops me up a message saying one of the fields is required. Then I realized I was seeing placeholder texts on them while we don't add them yet.

I opened my test file and experimented with the third one, the "email" input[type] attribute which I replaced with 'text' cause the css was just targeting the classic "text" and "password" input[type] values. And to my surprise, this attribute shows a warning when the input does not contain a valid email address.

After this I googled about html5 and saw the reference  page on w3.org . I pasted it on document editor and it appears to be 1000 pages, I trimmed it abit and came out to be 700 pages. I will print it(cause I don't like reading alot on computer screens) perhaps 200 pages a time then read about it to add up on my web developing knowledge.