ASP.NET web application - WebResource.axd and ScriptResource.axd files - Loading time issue
WebResource.axd and ScriptResource.axd references are embedded resources in the .NET Framework. WebResource.axd scripts are probably for web forms and validation while ScriptResource.axd is for ASP.NET AJAX.
You can combine the ScriptResource.axd scripts into one include by using the ToolkitScriptManager (part of the ASP.NET AJAX Control Toolkit).
I'm not sure of a way to combine the WebResource.axd scripts.
See this question for more on combining scripts.
jrummell is right on but if you want a detailed explanation of ways to improve that I would suggest this link:
ASP.NET AJAX Performance Improvement
It gives detailed information on script combining, turning on caching, and etc. Trust me it will help you speed it up.
I realize I'm a couple years late here, but for all you googlers out there, I just pushed a new release of my on the fly js/css minifier/merger RequestReduce that successfully merges Webresource and scriptresource files at run time.