IE10 giving me error 1509, unmatched end tag
html, internet-explorer-10
Solution
You can't have DIV (or any other block element) in a P unless you serve your markup as application/xhtml+xml. All pages served as text/html are parsed by HTML parser (in modern browsers, including IE10, it's HTML5 parser, regardless the doctype). In HTML, the content model of P element is 'phrasing content' (HTML5) or 'inline' (HTML4), and its end tag is optional in all versions of HTML. So the parser implicitly closes the P element before the opening tag of any block element. And in all browsers the DIV element will be not the child of P, but the sibling, and CSS selectors like p > div will never work for pages served as text/html.
Problem
In IE10, I create the following web page, and get an unmatched tag error: ``` <!DOCTYPE html> <html> <head> <title>Test</title> </head> <body> <p> <div> </div> </p> </body> </html> ``` I can find no problem with this code. I have narrowed it to having a div inside a paragraph as what is triggering the problem. IE10 reports: HTML1509: Unmatched end tag. test.php, line 12 character 2 and is pointing to the paragraph close token. An earlier me might have just ignored it. But I can't make myself do that any more. I have searched this site for something similar, but have found only legitimate syntax errors; valid explanations for the error, in other words. I know IE is brain-dead, but even post-Bill MSFT can't be silly enough to let a bug like that one, through (can they?). So I am assuming it's me, until proven otherwise. Possibly some subtlety of HTML5 I haven't grokked yet...