title: javascript how to get next week's date, and compare dates
body: <p>I am new to javascript. I wonder if there's any built-in methods that I could use.</p>
  
  <p>For example, given today is May 8 2014, I want my cell to show 'May 8 2014 - May 15 2014' In same month, I can just add the date by 7, but what about 'May 28 2014 - June 4 2014'? And how do I compare two dates? And how do I tell if a date is within that week period?</p>
  
  <p>Thanks for any ideas. </p>