I got an email today asking about the best way to go about adding the X-UA-Compatible tags on ASP.NET pages where you’ve got a master page, and may want to over ride the X-UA-Compatible tag in some content pages, but not others.
After playing around with it in Visual Studio for a few minutes, I pulled together the following scenarios:
Access To The Server
The optimal way to do this, if you have server level access, is to add the IE=EmulateIE7 as an HTTP Response Header from the server. Then, any pages served from that server will be rendered in IE7 mode. If Internet Explorer finds the X-UA-Compatible tag in both the HTTP Response Header, and as a META tag, the META tag will win out. Thus, if you've added the IE=EmulateIE7 to the server, you can over ride it by using the following code snippet:
protected void Page_Load(object sender, EventArgs e)
{
HtmlMeta xuac = new HtmlMeta();
xuac.HttpEquiv = "X-UA-Compatible";
xuac.Content = "IE=EmulateIE8";
Header.Controls.AddAt(0, xuac);
}
One quick note about the Page_Load method, you'll note I use the Header.Controls.AddAt(0, xuac) method. The X-UA-Compatible tag needs to occur BEFORE any code on the page is run, if it doesn't IE will ignore the X-UA-Compatible tag; so it's best to makes sure this is the first tag on the page.
No Server Access
If you don't have access to the server, and you want to put the X-UA-Compatible tag in the ASP.NET MASTER page, you could do something like this:
In the master page, I'd create a Content Place Holder:
<asp:ContentPlaceHolder ID="cphMeta" runat="server">
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />
</asp:ContentPlaceHolder>
Then, in the individual pages, where you want to override, and go to IE8 standards, you'd insert
<asp:Content ID="Content1" ContentPlaceHolderID="cphMeta" runat="server">
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE8" />
</asp:Content>
