leon2009sp,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
</style>
</head>
<body>
<table width="400" summary="" >
<tbody>
<tr>
<td align="center" background="http://javascript.ru/forum/images/smilies/smile.gif" id="img_1" onClick="chg(this.id)">1</td>
</tr>
</tbody>
</table>
<script>
function chg(id) {
var el = document.getElementById(id);
if (el.background.indexOf("http://javascript.ru/forum/images/smilies/smile.gif") === -1) {
el.background = "http://javascript.ru/forum/images/smilies/smile.gif";
} else {
el.background = "http://javascript.ru/forum/images/smilies/dance3.gif";
}
}
</script>
</body>
</html>