I am trying to run following HTML in every browser: Opera, FF, IE, Chrome
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="application/xhtml+xml; charset=utf-8">
</head>
<body>
<script>
<![CDATA[
alert('Hey!');
]]>
</script>
</body>
</html>
None of them display the alert. Chrome logs an error in console: Uncaught SyntaxError: Unexpected token <. It seems to be complaining about the fist < in CDATA declaration. Firefox also logs “syntax error”
The w3schools point out that this is the way to use CDATA http://www.w3schools.com/xml/xml_cdata.asp. Other answers on this site suggest it. What am I doing wrong? I tried playing with namespaces and doctypes, but that did not change anything.
Edit: I added XHTML name space and doctype, that I originally removed and the problem still persists.
The related question When is a CDATA section necessary within a script tag? explains that a CDATA section is recommended when embedding scripts in XHTML documents. However, just setting a XHTML doctype to the test document isn’t enough. The CDATA is still being treated as a syntax error.
According to this blog post, that is because the content type needs to match the doctype definition. Proper XHTML needs to have the following
Content-typeheader set:if that is not specified and
text/htmlsent instead, browsers will revert to HTML. And indeed, if I add that header to my test case, browsers start properly parsing the JavaScript inside the CDATA even when the CDATA it’s not commented out.This works for me (setting the header using PHP):