I think that this will do for your problem...
<script>
<!--
function submitForm(action) {
var f = document.f;
f.action = action;
f.submit();
}
//-->
</script>
<form name="f">
<input type="button" value=" Submit1 " onclick="submitForm('page1.php');">
<input type="button" value=" Submit2 " onclick="submitForm('page2.php');">
</form>