title: Changing the href attribute on checked
body: <p>I'm working on a web page that contains a radio buttons group. </p>
  
  <p>When one of these buttons get checked I need to change the href attribute of a link element (use different CSS file), How can I do that using Java script and html? </p>
  
  <p>I tried getElementById() but the innerHtml attribute doesn't help, do you have any simple solution?</p>