<html>
<body>
<script language="JavaScript">
function function1() {
var m = window.event.button;
if (m == 1) {
alert("The left button has been pressed");
} elseif (m == 2) {
alert("The right button has been pressed");
}
}
</script>
<div style="width:200;
height:200;
background-color:blue;
color:white;"
onmousedown="function1();">
Press on mouse while on top of this blue box.
</div>
</body>
</html>