title: Changing a CSS rule-set from Javascript
body: <p>Is it possible to make changes to a CSS rule-set dynamically (i.e. some JS which would change a CSS rule-set when the user clicks a widget)</p>
  
  <p>This particular CSS rule-set is applied to lots of elements (via a class selector) on the page and I want to modify it when the user clicks the widget, so that all the elements having the <strong>class</strong> change.</p>