http://pub9.ezboard.com/ffz2kcode.showMessage?topicID=790.topic


<script language="JavaScript">
<!--
function detect_touche(zone)
{
touche = event.keyCode;
switch (touche) 
{
case 13 :
document.mapage.html.submit();
event.keyCode = 0;
event.returnValue = false; 
break;
default :
return 0;
}
//-->
</script>



dans imput 

onKeydown=detech_touche ( this)


<input type="image" src="../images/valider.jpg" width="64" height="23" name=".submit" onKeydown=detech_touche ( this) alt="Cliquez ici pour envoyer" border="0">

http://www.devguru.com/Technologies/html/quickref/html_core_onkeypress.html