I recently had to open links in an IFrame in a new window.  The problem before was files ilke PDFs and images were opening up in the IFrame with no scrolling.  I wanted a clean, quick solution with JQuery so below is what I came up with. 

$(document).ready(function() {
        $('a').click(function() {
        window.open($(this).attr('href'), 'File', 'fullscreen=yes', 'resizable,scrollbars'); return false;
    });
});

I have tried many ways to get the root/base url of a website.  A static approach to this is to store it in the web.config appsettings section and calling it in code.

<appSettings>
        <add key="RootUrl" value="http://www.mydotnetworld.com"/>
</appSettings>

string rootUrl = ConfigurationManager.AppSettings["RootUrl"];

This isnt convenient when you are working locally and the port number might change.  Another way is to call a method to get the base/root of the website.  I have seen numerous ways to do this and most of them had flaws.  I created my own that I use in every project and hasnt failed me yet.  It works in any development environment.

I place this function inside a utility class and call it wherever the base/url is needed.  It also comes in handy within javascript.

var rooUrl = <%= Utility.RootUrl %>;