calling GetCapabilities reports text/javascript for JSONP is not available for GetFeatureInfo. Other types are included in the list.
according to GeoServer docs @ http://docs.geoserver.org/latest/en/user/services/wms/reference.html this should be possible
this is a fresh install of geoserver 2.6.2 running as a service on Windows 8.1
we set ENABLE_JSONP true in\webapps\geoserver\WEB-INF\web.xml and restarted the GeoServer serveice
wrapper.log reports as follows;
INFO | jvm 1 | 2015/03/02 12:38:16 | org.geowebcache.mime.MimeException: Unsupported format request: text/javascript
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geowebcache.mime.MimeType.createFromFormat(MimeType.java:134)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.gwc.layer.GeoServerTileLayer.getInfoMimeTypes(GeoServerTileLayer.java:1105)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geowebcache.service.wms.WMSGetCapabilities.capabilityRequestGetFeatureInfo(WMSGetCapabilities.java:303)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geowebcache.service.wms.WMSGetCapabilities.capability(WMSGetCapabilities.java:215)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geowebcache.service.wms.WMSGetCapabilities.generateGetCapabilities(WMSGetCapabilities.java:125)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geowebcache.service.wms.WMSGetCapabilities.writeResponse(WMSGetCapabilities.java:86)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geowebcache.service.wms.WMSService.handleRequest(WMSService.java:288)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geowebcache.service.wms.WMSService$$FastClassByCGLIB$$85c0e55b.invoke(<generated>)
INFO | jvm 1 | 2015/03/02 12:38:16 | at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:191)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:689)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.gwc.config.GWCServiceEnablementInterceptor.invoke(GWCServiceEnablementInterceptor.java:47)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:622)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geowebcache.service.wms.WMSService$$EnhancerByCGLIB$$e0331eae.handleRequest(<generated>)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geowebcache.GeoWebCacheDispatcher.handleServiceRequest(GeoWebCacheDispatcher.java:344)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geowebcache.GeoWebCacheDispatcher.handleRequestInternal(GeoWebCacheDispatcher.java:254)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:153)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.gwc.dispatch.GwcServiceProxy.dispatch(GwcServiceProxy.java:98)
INFO | jvm 1 | 2015/03/02 12:38:16 | at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
INFO | jvm 1 | 2015/03/02 12:38:16 | at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
INFO | jvm 1 | 2015/03/02 12:38:16 | at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
INFO | jvm 1 | 2015/03/02 12:38:16 | at java.lang.reflect.Method.invoke(Unknown Source)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.ows.Dispatcher.execute(Dispatcher.java:792)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.ows.Dispatcher.handleRequestInternal(Dispatcher.java:274)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:153)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
INFO | jvm 1 | 2015/03/02 12:38:16 | at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
INFO | jvm 1 | 2015/03/02 12:38:16 | at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1093)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.filters.ThreadLocalsCleanupFilter.doFilter(ThreadLocalsCleanupFilter.java:28)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.filters.SpringDelegatingFilter$Chain.doFilter(SpringDelegatingFilter.java:75)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.wms.animate.AnimatorFilter.doFilter(AnimatorFilter.java:71)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.filters.SpringDelegatingFilter$Chain.doFilter(SpringDelegatingFilter.java:71)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.filters.SpringDelegatingFilter.doFilter(SpringDelegatingFilter.java:46)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.platform.AdvancedDispatchFilter.doFilter(AdvancedDispatchFilter.java:50)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:311)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter$NestedFilterChain.doFilter(GeoServerCompositeFilter.java:69)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter$NestedFilterChain.doFilter(GeoServerCompositeFilter.java:73)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter.doFilter(GeoServerCompositeFilter.java:92)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter$NestedFilterChain.doFilter(GeoServerCompositeFilter.java:69)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter$NestedFilterChain.doFilter(GeoServerCompositeFilter.java:73)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter.doFilter(GeoServerCompositeFilter.java:92)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerAnonymousAuthenticationFilter.doFilter(GeoServerAnonymousAuthenticationFilter.java:54)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter$NestedFilterChain.doFilter(GeoServerCompositeFilter.java:69)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter$NestedFilterChain.doFilter(GeoServerCompositeFilter.java:73)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter.doFilter(GeoServerCompositeFilter.java:92)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerBasicAuthenticationFilter.doFilter(GeoServerBasicAuthenticationFilter.java:83)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter$NestedFilterChain.doFilter(GeoServerCompositeFilter.java:69)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerSecurityContextPersistenceFilter$1.doFilter(GeoServerSecurityContextPersistenceFilter.java:53)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter$NestedFilterChain.doFilter(GeoServerCompositeFilter.java:73)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.filter.GeoServerCompositeFilter.doFilter(GeoServerCompositeFilter.java:92)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:173)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.security.GeoServerSecurityFilterChainProxy.doFilter(GeoServerSecurityFilterChainProxy.java:135)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.filters.LoggingFilter.doFilter(LoggingFilter.java:76)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.filters.GZIPFilter.doFilter(GZIPFilter.java:42)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.filters.SessionDebugFilter.doFilter(SessionDebugFilter.java:48)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.geoserver.filters.FlushSafeFilter.doFilter(FlushSafeFilter.java:44)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.vfny.geoserver.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:109)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:726)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:206)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.Server.handle(Server.java:324)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:828)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:514)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
INFO | jvm 1 | 2015/03/02 12:38:16 | at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:450)