<SCRIPT type="text/javascript">
var func;
function compute() {
  func = document.forms[1].formel.value;
  // Die Elemente eines Formulars können über ihren Index angesprochen werden.
   for (x = -5; x <= 5; x++) {
    document.forms[0].elements[5+x].value = eval(func).toString();
   }
}
function compute2() {
  var x, mitte, y1, y2, ymitte;
  var x1   = parseFloat(document.forms[1].xmin.value);
  var x2   = parseFloat(document.forms[1].xmax.value);
  x=x1;  y1 = eval(func);
  x=x2;  y2 = eval(func);
  if (y1*y2 > 0) alert("Gib ein geeignetes Intervall an!")
  else {
    while (Math.abs(x2-x1) > 0.0000000000001) {
      mitte = (x1+x2)/2; x = mitte;  ymitte = eval(func);
      if (y1*ymitte > 0) x1 = mitte
      else x2= mitte;
      x=x1;  y1 = eval(func);
      x=x2;  y2 = eval(func);
    } //while
  mitte = Math.round(mitte*10000000000)/10000000000;
  document.forms[1].nullstelle.value = mitte.toString();
  } //else
} //function
</SCRIPT>