As I said in this post, there are plenty of articles on how to do this. This is more of a note for myself, as I have to “re-learn” this every time I need to customize SharePoint.

There are 2 ways (that I know of) that you can add code to every page in SharePoint 2010, 1 by the AdditionalPageHead delegate control, or ,2 by Custom Action. This article is about #1 (see #2 here) using the AdditionalPageHead delegate control.

• Start Visual Studio, and create a new Empty SharePoint Project (uncheck the Create Directory for Solution because you salways create the destination directory yourself)
• Deploy as a Farm Solution (I have not figured what you can and can’t do with sandboxed solutions yet)
• RightClick the Project and Add –> New item –> User Control –Name it. This will create a new folder named ControlTemplates and inside will be your User Control. Looks like this

• Edit the new ascx file and add the code you want to put at the top of every page, for example:

<script type="text/javascript" src="/path/to/jquery.js"></script>

• RightCLick the Project and select Add Empty Element and name it at the bottom
• add the following to the elements.xml file. The final should look like this below:

  <Control Id="AdditionalPageHead"
          Sequence="90"
          ControlSrc="~/_CONTROLTEMPLATES/DelegateControl/DelegateControl.ascx" />

Package everything up and you will now see your reference to jQuery on the top of all pages.