I have several Content Pages using the same Master Page, that don't all need the same javascript and css files included in the <head> tag.
Is it possible to change the contents of the <head> tag from the Content Pages?
it is, but I recommend doing it a bit different. I place a content place holder right above the close body tag. Then I populate the required JS scripts per content page. This will allow you to place the scripts at the bottom, but you could also do the same with the placeholder in the header.
You can also do so programmatically:
HtmlGenericControl js = new HtmlGenericControl("script");
js.Attributes["type"] = "text/javascript";
js.Attributes["src"] = "jscript/jquery.js";
Page.Header.Controls.Add(js);
Put a Placeholder control in the head and you should be able to use that in the content pages.
来源：https://stackoverflow.com/questions/3338022/can-i-include-different-javascript-css-files-per-content-page-using-asp-net-webf