codice:
<html>
<head>
<script type="text/javascript" language="JavaScript">
<!--
function changeThumbnail( __hForm )
{
var _curSelectionId = __hForm.elements["imgList"].selectedIndex;
document.images["thumbImg"].src = __hForm.elements["imgList"].options[_curSelectionId ].value;
}
//-->
</script>
</head>
<body>
<form onsubmit="changeThumbnail( this ); return false;">
[img]default.gif[/img]
<select name="imgList">
<option value="http://www.sito.it/img1.gif">Immagine #1</option>
<option value="http://www.sito.it/img2.gif">Immagine #2</option>
<option value="http://www.sito.it/img3.gif">Immagine #3</option>
<option value="http://www.sito.it/img4.gif">Immagine #4</option>
</select>
<input type="submit" value=" MOSTRA ANTEPRIMA " />
</form>
</body>
</html>