How to call webservice using javascript

hello, i m use javascript to call webservice.
it working well on local but server it not working.
my code.
for calling:
function CallWebService() {
            var objXMLHttpRequest = CreateXMLHttpRequest();
            //objXMLHttpRequest.open("POST", "http://localhost:30179/SampleWebService.asmx", false); ----local working well
            objXMLHttpRequest.open("POST", "http://mysitexyz.com/SampleWebService.asmx", false);  // here server not working
            objXMLHttpRequest.setRequestHeader("Content-Type", "text/xml; charset=utf-8");
          
          var packet = '<?xml version="1.0" encoding ...