Script elements accumulate when using jsonp. I could be missing something, but this block of code in $.ajax doesn't make sense to me:

// Handle Script loading
if ( !jsonp && (s.success || s.complete) ) {
    var done = false;

    // Attach handlers for all browsers
    script.onload = script.onreadystatechange = function(){
        if ( !done && (!this.readyState || 
                this.readyState == "loaded" || this.readyState == "complete") ) {
            done = true;
            success();
            complete();
            head.removeChild( script );
        }
    };
}

Why is removing the script element conditional on no jsonp and the presence of callbacks?