Question

I’m implementing Bing Maps on a page (I’d prefer Google Maps, but it’s not my choice). I’m following the tutorial MS provides here: http://msdn.microsoft.com/en-us/library/bb412551.aspx

Using MS’s code, everything worked just fine. Fleshing it out with some of my own jQuery code, I found that I was getting a “Permission Denied” error every time I ran $.get(); I assumed this was some sort of “Same Origin” conflict, but after much checking, I determined that I wasn’t requesting anything from any other host (not even http://www.example.com vs. example.com – everything was on the SAME host).

After much frustration, I finally whittled the cause down to the META tag in MS’s code:

<meta http-equiv="Content-Type" content="text/html; charset=utf-8">

This was towards the bottom of my HEAD section. In reading the spec. for the META tag (which I wasn’t very familiar with), I found that some servers may translate http-equiv tags directly into HTTP headers, while others may just send them as-is. Since I believe headers must be sent before any content, I moved the META tag to the BEGINING of the HEAD section, and everything worked fine.

Another detail: I only had problems in IE7. When I tested in FF, I had no problems at all.

So here’s my question: Are META tags with the http-equiv attribute SUPPOSED to be at the begining of the HEAD section? Was IE just being weird? Or was FF just being particularly forgiving?

Thanks!

Answer 1

From the HTML5 draft spec (http://dev.w3.org/html5/spec/semantics.html#charset):

4.2.5 The meta element

[snip]

4.2.5.5 Specifying the document’s character encoding

Status: Last call for comments

A character encoding declaration is a mechanism by which the character encoding used to store or transmit a document is specified.

The following restrictions apply to
character encoding declarations:

* The character encoding name given must be the name of the character encoding 
  used to serialize the file.
* The value must be a valid character encoding name, and must be an ASCII
  case-insensitive match for the preferred MIME name for that encoding. 
  [IANACHARSET]
* The character encoding declaration must be serialized without the use of 
  character references or character escapes of any kind.
* The element containing the character encoding declaration must be serialized
  completely within the first 512 bytes of the document.
* There can only be one character encoding declaration in the document.

Note the fourth bullet point. I believe that the 512 byte rule was a compromise between the legacy browsers which have in the past chosen different limits, but all, I think, had a byte limit of some length. This may be the reason, though why it should cause a “Permission Denied” error, I’ve no idea.