Applet code:
<applet code=com.objectplanet.chart.ChartApplet
 archive=chart.jar width=450 height=300 name=BarChart VIEWASTEXT>
<param name=chart value="bar">
<param name=sampleColors value="#3D7778">
<param name=background value="white">
<param name=sampleValues value="20,10,40,30,50">
<param name=overlay0 value="line">
<param name=overlay0_lineWidth value="5">
<param name=overlay0_sampleValues value="15,7.5,30,22.5,37.5">
<param name=overlay0_sampleColors value="#D10069">
<param name=overlay1 value="line">
<param name=overlay1_sampleValues value="10,5,20,15,25">
<param name=overlay1_sampleColors value="#6EA7DB">
<param name=overlay1_stackedOn value=true>
</applet>


<form name="input">
overlay 1
<INPUT NAME="overlay1" type=checkbox checked onClick=repaint()>
overlay 2
<INPUT NAME="overlay2" type=checkbox checked onClick=repaint()>
</form>

<script LANGUAGE="JavaScript">
<!--
function repaint() {
	document.BarChart.chart.setOverlayChartOn(0, document.input.overlay1.checked);
	document.BarChart.chart.setOverlayChartOn(1, document.input.overlay2.checked);
}
//-->
</script>