title: get selected cell's value and address in Office.js excel
body: <p>I am working on a <code>Excel Web Add-In</code> using <code>Office.js</code>. I need to get selected cell's <code>Address</code> and <code>Value</code>. Please be clear that here user will select only one cell.</p>
  
  <p>This should happen when user click on cell in worksheet.</p>