I have been trying for a week now to reduce the number of requests on our web application but I can’t seem to combine the .axd files. I got a suggestion from somewhere which worked locally (development box) but doesn’t work on our test and production environment as they are both on HTTPS. The developer didn’t comment on that and the component he wrote was last updated in 2011. (I will find the link and update this post).
I tried using the CompositeScript in ScriptManager and again it doesn’t work on Test/Production environments.
I used SquishIt to resolve the other files. (see attachment)

Answers:
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Method 1
To force it work on your environment, set ScriptMode="Release" eg as:
<asp:ScriptManager ID="ScrMang" runat="server" ScriptMode="Release" >
<CompositeScript>
<Scripts>
<asp:ScriptReference name="MicrosoftAjax.js"/>
<asp:ScriptReference name="MicrosoftAjaxWebForms.js"/>
<asp:ScriptReference name="Common.Common.js" assembly="AjaxControlToolkit"/>
</Scripts>
</CompositeScript>
</asp:ScriptManager>
Some more notes
To find what scripts to add inside CompositeScript you can use the code from here : http://aspnet.codeplex.com/releases/view/13356 and get more help how to use it from this page : https://lancezhang.wordpress.com/2008/11/15/aspnet-ajax-performance/
All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0