Example of an interactive animation

<SCRIPT>
function infoFromJava_Slider(sliderName,waarde)
{
  document.formA.field1.value = waarde;
}

function reStart()
{
  t = 0.0; 
  dt = 0.0005;
  x = 1.0;
  y = 1.0;
  a = 1.0;
  i = 150;
  j = 150;

  document.slider1.setPMax(2.0); 
  document.slider1.setPMin(0.0);
  document.slider1.setPStart(1.0);
  document.slider1.setDigits(4);

  document.vogel1.setX(Math.round(i));
  document.vogel1.setY(Math.round(j));

  document.formA.field2.value = t;
}

function run()
{
  iii = document.formA.field1.value;
  a = parseFloat(iii);

  t = t + dt; 

  x = a*Math.sin(2*3.14*t);
  y = a*Math.cos(2*3.14*t);

  i = 100*x + 150;  
  j = -100*y + 150;

  document.vogel1.setX(Math.round(i));
  document.vogel1.setY(Math.round(j));

  document.formA.field2.value = t;

  if (t<1.0) {window.setTimeout("run();",5)}; 
}
</SCRIPT>

 .
 .

<CENTER> 
<FORM NAME="formA">
 
<APPLET
    code=slider.class
    NAME=slider1
    width=300
    height=16 MAYSCRIPT>
</APPLET>  

<INPUT TYPE="text" NAME="field1" VALUE="aaaa" SIZE="10"><BR>
<INPUT TYPE="button" name="Start" value="Set" onClick="reStart(this.form)"><BR>
<INPUT TYPE="button" name="Run" value="Run" onClick="run(this.form)"><BR>
<INPUT TYPE="text" NAME="field2" VALUE="bbbb" SIZE="10"><BR>

<APPLET
    code="Piranihan.class"
    NAME=vogel1
    width=300
    height=300>
</APPLET>

</FORM>
</CENTER> 

Enschede, 2 maart 2000; update: Febr. 2004