JavaScript Error occured with JSONP in bookmarklet

Question

The following Error occured in FireBug Firefox3.5.2

Failed to load source for: http://example.com/

My bookmarklet is

javascript:(
    function(){
        window.callback = function(d){alert(d)};
        var script = document.createElement('script');
        script.setAttribute("type", "text/javascript");
        script.setAttribute("charset", "UTF-8");
        script.setAttribute("id", (new Date()).getTime());
        script.src="http://example.com/api/function.php?callback=window.callback";
        document.body.appendChild(script);
    }
)();

callback is:

window.cb && window.cb({"key":"value"});

What's wrong?

Answer 1

If you're really loading from a PHP page, I would make sure that page is returning a text/javascript MIME type.