<!--
function calc(fn)
{
  var entry = document.LCD.Display.value;

//check for non-digits entry

  var checkOK = "0123456789.*+ -/^()";
  
  var allValid = true;
  for (i = 0;  i < entry.length;  i++)
  {
    ch = entry.charAt(i);
    for (j = 0;  j < checkOK.length;  j++)
      if (ch == checkOK.charAt(j))
        break;
    if (j == checkOK.length)
    {
      allValid = false;
      break;
    }
  }
if (!allValid)
  {
    document.LCD.Display.value = "NaN"
  }
else if (allValid)
 { 
  if (fn == 'sin' ) 
  { document.LCD.Display.value = eval(Math.sin(eval(document.LCD.Display.value) * (Math.PI/180))) }
  else if (fn == 'asin' ) 
  { document.LCD.Display.value = eval(Math.asin(eval(document.LCD.Display.value)) * (180/Math.PI)) }
  else if (fn == 'cos' ) 
  { document.LCD.Display.value = eval(Math.cos(eval(document.LCD.Display.value) * (Math.PI/180))) }
  else if (fn == 'acos' ) 
  { document.LCD.Display.value = eval(Math.acos(eval(document.LCD.Display.value)) * (180/Math.PI)) }
  else if (fn == 'tan' ) 
  { document.LCD.Display.value = eval(Math.tan(eval(document.LCD.Display.value) * (Math.PI/180))) }
  else if (fn == 'atan' ) 
  { document.LCD.Display.value = eval(Math.atan(eval(document.LCD.Display.value)) * (180/Math.PI)) }
  else if (fn == 'log' ) 
  { document.LCD.Display.value = eval(Math.log(eval(document.LCD.Display.value))) }
  else if (fn == 'pow' ) 
  { var num = document.LCD.Display.value;
    var s = num.split("^")
  document.LCD.Display.value = eval(Math.pow(eval(s[0]),eval(s[1]))) }
  else if (fn == '1/x' ) 
  { document.LCD.Display.value = eval(1/(eval(document.LCD.Display.value))) }
  else 
  {
   document.LCD.Display.value = eval(document.LCD.Display.value)
   }
 }
}



//-->