title: javascript and element location
body: <p>I want to get up to speed on element location and javascript.</p>
  
  <p>ie. if someone clicks on an element, I can show a menu just below that element.</p>
  
  <p>Now I realize I have to account for the fact that if someone clicks on a element to the extreme left/right or bottom of the page, I have to know if the menu is visible on the screen properly.</p>
  
  <p>This seems complicated and would love if there is some tutorial on this very topic?</p>