Can a <hr /> element have a closing tag?_问答_开发者

Can a <hr /> element have a closing tag?

开发者 https://www.devze.com 2023-03-14 21:31 出处：网络

My colleague doesn\'t really know or understand html. Her job is to input information into the CMS and I\'ve noticed she keeps closing her <hr /> tags like this <hr></hr>.

相关专题：xhtml

My colleague doesn't really know or understand html. Her job is to input information into the CMS and I've noticed she keeps closing her <hr /> tags like this <hr></hr>.

I've had a Google but I can't find anywhere that says this isn't allowed or could cause problems. I know it's supposed to be <hr /> but is it worth me telling her or is it unnecessary but valid markup?

NB The doctype for our website is XHTML 1.0 Transitional if 开发者_StackOverflowthat makes any difference.

EDIT

@Jeff had a good idea about validating. I used the following code and apparently this is valid XHTML 1.0 Transitional

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <title></title>
    </head>
    <body>
        <hr></hr>
    </body>
</html>

OK, <hr></hr> is actually a valid XHTML 1.0, too.

So, for XHTML 1.0:

<hr /> is valid
<hr></hr> is valid
<hr> is not valid

... for HTML 4.0:

<hr /> is valid
<hr></hr> is not valid
<hr> is valid

therefore the best option is to use <hr />, which is always valid.

HTML 4 says:

Start tag: required, End tag: forbidden

And as XHTML basically means that HTML tags need to have a closing tag, I would say <hr /> is the only format you should consider.

As the others say, <hr></hr> is valid XHTML (they even use it as example) but for compatibility reasons I would not use it.

<hr /> is merely shorthand for <hr></hr>; both are acceptable in XHTML documents. However, neither are acceptable in HTML documents, where <hr> should be used instead, which in turn is invalid in XHTML.

No. <hr /> should not have a closing tag.

It is invalid HTML.

It is valid XML and therefore technically it's valid xhtml, but you still shouldn't use it, even if you're using xhtml.

This is because all the browsers actually use their HTML parser even when rendering xhtml code, and therefore the a closing </hr> tag is seen as an error. Some browsers may even mis-interpret it as an additional <hr> element.

The only cross-browser compatible way of doing it is either <hr> (ie plain HTML) or <hr /> if you want to have a valid xhtml document.

As far as I know there is no closing hr tag. The tag is purely self closing and the Doc Type Definition will reflect this.

Since it's an empty element, it makes no sense to have open and close tags.

However, XML requires all tags to be closed, hence the <hr /> form.

I suppose in HTML, not XML, <hr></hr>is valid, but unnecessary.

The HR element draws a horizontal rule. This is a block element and does not require a closing tag.

Ref: http://msdn.microsoft.com/en-us/library/bb159725.aspx