description(s)


  <h5>
  y=<span id="fval">f</span>
  <input type="text" id="fv" name="fname" value="cube(x)" onblur="toggle()" />
  for <span id="maval">a <=x<= a</span>
  <input type="button" value="-" onclick="a-=.25;update()"/>
  <input type="button" value="+" onclick="a+=.25;update()"/>
  </h5>
  </center>
  </body>