I want a strict but fully compatible html5 alternative to:
<!doctype html>
Basically I want to ensure the use of closing tags just to keep everything well readable, consistent and highlighted clearly in editors.
The answer to this question is to HTML 5, as XHTML-1.0-strict is to HTML 4.
Thanks in advance.
There is no doctype for "strict" XHTML5 validation. For XHTML5 the doctype is even optional, as the doctype is only for stopping the browser to switch to quirksmode. There is no such quirksmode for XHTML. It is recommended to use the HTML5 doctype (with capitalised DOCTYPE) if you are planning to use it as a polyglot document. In that case you would use the doctype:
<!DOCTYPE html>
However, if you want to validate as if the document is using XHTML style syntax, you can achieve that using the advanced options of the validator.
Go to http://validator.nu
Switch to "text field" in the select box (or point it to your online document but make sure it is served as XHTML not text/html
If using the text field paste in your document. In my case I used the following:
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<meta charset="UTF-8" />
</head>
<body>
<p>test
</body>
</html>
Select XHTML5 + SVG 1.1 + MathML 3.0 from the Preset field. This will pre fill the scheme as http://s.validator.nu/xhtml5.rnc http://s.validator.nu/html5/assertions.sch http://c.validator.nu/all/
Click Validate
Using my document it will warn about the missing close </p>.
Related
Why is <!DOCTYPE html ... > used in html file?
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
The DOCTYPE Declaration (DTD or Document Type Declaration) does a couple of things:
When performing HTML validation testing on a web page it tells the HTML (HyperText Markup Language) validator which version of (X)HTML standard the web page coding is supposed to comply with. When you validate your web page the HTML validator checks the coding against the applicable standard then reports which portions of the coding do not pass HTML validation (are not compliant).
It tells the browser how to render the page in standards compliant mode.
For more information refer to this "<!DOCTYPE html>" What does it mean?
It tells the browser that the following code is to be treated as a particular version of html code.
The browser knows then to look for an open HTML tag <html> and treats everything like html until it reaches the close HTML tag </html>
<!DOCTYPE html> is all that's needed now.
The term DOCTYPE tells the browser which type of HTML is used on a webpage. Here is link of official page which explains your query why and what is
<!DOCTYPE html>
A doctype defines which version of HTML/XHTML your document uses. You would want to use a doctype so that when you run your code through validators, the validators know which version of HTML/XHTML to check against
The declaration is not an HTML tag; it is an instruction to the web browser about what version of HTML the page is written in.
In HTML 4.01, the declaration refers to a DTD, because HTML 4.01 was based on SGML. The DTD specifies the rules for the markup language, so that the browsers render the content correctly.
HTML5 is not based on SGML, and therefore does not require a reference to a DTD.
Tip: Always add the declaration to your HTML documents, so that the browser knows what type of document to expect.
The <!DOCTYPE html> declaration is used to inform a website visitor's browser that the document being rendered is an HTML document. While not actually an HTML element itself, every HTML document should being with a DOCTYPE declaration to be compliant with HTML standards.
For HTML5 documents (which nearly all new web documents should be), the DOCTYPE declaration should be:
<!DOCTYPE html>
Show to the browser than the file is a HTML5.
Is followed by the lenguage etiquete according to HTML5 good practiques.
<!doctype html>
<html lang="es">
In this case the second line indicates to the browsers than the file is in example, spanish in this case <html lang="es">
is important for building an HTML documents it is not just HTML but it is an instruction to the web browser about what version of HTML the page is written in.
I am working with this Web Page for improving my programming skills:
http://www.studenti.ict.uniba.it/esse3/ListaAppelliOfferta.do
If you take a look at its source code, you can see HTML peculiar tags like
<head> <body> <title>
The question is: I am quite sure this page is not in XML, so is it simple HTML or XHTML?
According to my knowledge those two are quite similar.
How can I tell which of the two it is? If I must choose I'd say simple HTML (5 or 4) but I am not 100% sure!
Look for a Doctype declaration at the very beginning of the document.
If it is XHTML, the doctype will look like this:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
If it is HTML5, it will look like this:
<!DOCTYPE html>
See the W3 Spec for information on Doctype. More information here at the Mozilla Developer Network, too.
The Website you linked has <!DOCTYPE html> declared, which instructs the browser to interpret the document as HTML5 markup.
The <!DOCTYPE html> declaration indicates that it is HTML5. Of course, it might not actually be HMTL5, but it's claiming that it is. The only way to be sure is to run it through an HTML5 validator.
From: http://www.w3schools.com/tags/tag_doctype.asp
The < !DOCTYPE > declaration is not an HTML tag; it is an instruction to
the web browser about what version of HTML the page is written in.
In HTML 4.01, the < !DOCTYPE > declaration refers to a DTD, because HTML
4.01 was based on SGML. The DTD specifies the rules for the markup language, so that the browsers render the content correctly.
HTML5 is not based on SGML, and therefore does not require a reference
to a DTD.
Tip: Always add the < !DOCTYPE > declaration to your HTML documents, so that the browser knows what type of document to expect.
Does the bold statement mean that when we are using HTML 5 we don't need to specify < !DOCTYPE html >?
What does that statement exactly mean?
I am currently using < !DOCTYPE html > in my html file with the browser Firefox 4. I removed that declaration but did not see any difference in the rendered output. Does it mean that the problem may occur in old browsers and not in new ones?
The terminology is confusing, but a DTD (document type definition) is only one part of a document type declaration (usually shortened to "doctype"). You should always include a doctype declaration (<!DOCTYPE html> if you use HTML5), but a document type definition identifier is no longer necessary.
To provide a concrete example, this is what a HTML4.01 document type declaration ("doctype") might have looked like:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
The document type definition ("DTD") identifier in the above declaration is this part:
"-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"
That's the part you can leave off for HTML5. "PUBLIC" specifies the DTD's availability, so that should also not be included if there is no DTD.
Does the bold statement mean that when we are using HTML 5 we don't need to specify ?
It means that you can't specify.
The HTML 5 Doctype has no public or system identifier in it.
I am currently using <!DOCTYPE html> in my html file
That is required. Keep doing that.
with the browser Firefox 4.
The current stable version of Firefox is version 20. You should probably upgrade.
I removed that declaration but did not see any difference in the rendered output. Does it mean that the problem may occur in old browsers and not in new ones?
No, it just means that you don't have any code that is impacted by being in Quirks mode (or that you do but didn't spot the changes).
Lets take a look at the W3C HTML5 definition, they have a conveniënt page about the differences HTML5 brings:
http://www.w3.org/TR/html5-diff/#doctype
2.2 The Doctype
The HTML syntax of HTML5 requires a doctype to be specified to ensure
that the browser renders the page in standards mode. The doctype has
no other purpose. [DOCTYPE]
The doctype declaration for the HTML syntax is and is
case-insensitive. Doctypes from earlier versions of HTML were longer
because the HTML language was SGML-based and therefore required a
reference to a DTD. With HTML5 this is no longer the case and the
doctype is only needed to enable standards mode for documents written
using the HTML syntax. Browsers already do this for .
To support legacy markup generators that cannot generate the preferred
short doctype, the doctype is allowed in the HTML syntax.
The strict doctypes for HTML 4.0, HTML 4.01, XHTML 1.0 as well as
XHTML 1.1 are also allowed (but are discouraged) in the HTML syntax.
In the XML syntax, any doctype declaration may be used, or it may be
omitted altogether. Documents with an XML media type are always
handled in standards mode.
On that page, chapter 1 (Introduction) says more about HTML versus XML syntax:
The HTML5 draft (..) defines a single language called HTML which can be written in HTML syntax and in XML syntax.
So, if your HTML5 is strict XML syntax, i can conclude from the last paragraph that yes in this case you should not prefix a doctype line.
See chapter 2 for the difference in syntax:
HTML5 HTML syntax:
<!doctype html>
<html>
<head>
<meta charset="UTF-8">
<title>Example document</title>
</head>
<body>
<p>Example paragraph</p>
</body>
</html>
HTML5 XML syntax:
<?xml version="1.0" encoding="UTF-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Example document</title>
</head>
<body>
<p>Example paragraph</p>
</body>
</html>
There is some subtle differences in syntax.
When writing a html 5 doctype, are you supposed to include the <html xmlns="http://www.w3.org/1999/xhtml"> as you did when previously using HTML4 doctype or should a different xhtml be used?
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
HTML5 does not require the use of the xmlns attribute as that is specific to XHTML (which means not even HTML 4 uses it either).
If you're just serving regular HTML5, then you can leave out that attribute entirely:
<!DOCTYPE html>
<html>
The xmlns attribute is only required if you're writing and serving XML-serialized HTML5, aka XHTML5.
No, you don't need to include it. This should be enough.
<!doctype html>
<html>
No you don't. In fact, if you include it, then it isn't HTML5, it's xhtml.
The xmlns part is an XML namespace reference. HTML5 is not XML.
In fact, if you were using that xmlns previously, then you weren't using HTML4 either, you were using xhtml. They're not the same.
I have a large dynamic website that is being constructed by PHP. I suspect that one of my components are not closing the HTML tags properly. I have the source output HTML. I am wondering if there is a script, or website, that will tell me if all my tags are closed and such?
Use the W3C Markup Validator Service at http://validator.w3.org/
Just for interest, I shall point out that validator.nu is better for checking HTML4 than the W3C validator. Suppose your markup is this:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta content="Test" /
<title>Test Case</title>
</head>
<body>
<p></p>
</body>
</html>
The <meta> element clearly isn't closed where it should be, and the result is that the <title> element won't be recognised in browsers.
But give that markup to the W3C validator and it will tell you that it validates. That's because it is based on SGML processing which permits a syntax known a Null End Tag (NET) syntax, which makes it think that the / ends the tag.
Browsers do not support NET syntax, and neither does validator.nu, thus correctly flagging the markup as in error.
For HTML5, both validators are good.
Try HTML Tidy. Theres a firefox plugin version as well
If you work alot in your browser and dont want to jump back and forth to the w3 schools this is a good choice, but like everyone who commented said, the validator is good as well.
This Website checks if there are unclosed tags, and tells you which ones are not closed, and the line they belong