Since 1.4.0-rc1 and confirmed in 1.4.1, calling $http.delete('url') in IE10 causes a non-zero Content-Length header to be added to the request. I noticed this when the webserver was returning HTTP error code 415 on all $http.delete calls.

I tracked this down to 1.4.0-rc1 where xhr.send(post || null) in createHttpBackend was changed to xhr.send(post). When post is undefined, this problem occurs in IE10. The code below reproduces this bug in IE10 and is essentially what $http.delete('url') is doing.

var xhr= new window.XMLHttpRequest();
var post;
xhr.open('DELETE', 'url', true);
xhr.send(post);

Changing xhr.send(post) to xhr.send(post || null) fixes the problem.