Are there any fundamental differences in the way Firefox 3.5 and Opera 10.0 implement the XMLHTTPRquest Objects? After implementing a asmx web service which performs transformations given (well-formed) XML and xsl, I have found that Firefox response times are extremely slow (i.e. +2s) compared to Opera 10 (-1s). I would assume this latency can be attributed to each browsers implementation of XMLHTTPRequest however i do not know enough about this at this point. I have however found that the latency in Firefox occurs for the most part when waiting for the response from the server (e.g. 0ms Connecting, 0ms Queuing, 1.01s waiting for response, 1ms receiving data). This 'waiting for response' period is significantly shorter in Opera. Does anyone know enough about this to advise as to how this 'waiting for response' time can be reduced? My Web services are .NET web services and i am invoking them using JavaScript.