<html>
<head>
<script>
function mouseDownInfoDialog(e,idDialog)
{
alert(e.clientX);
$(idDialog).style.display="block";
}
</script>
</head>
<body>
<img id="imageInfoDialog" class="imgInfo" onmousedown="mouseDownInfoDialog(event,'aboutProgram'); this.style.opacity=1;" onmouseup="this.style.opacity=0.8;" onmouseover="this.style.opacity=0.8;" onmouseout="this.style.opacity=0.5;" src="images/ico_info.png" alt="О программе" title="О программе" />
</body>
</html>
почему?