<? 
echo "Filename : ".$_FILES['fff']['name']."<br>"; 
echo "Tmp_name : ".$_FILES['fff']['tmp_name']."<br>"; 
?> 
<html> 
<body> 
<form name=aaa action="test4.php" method="post" enctype="multipart/form-data"> 
<input type=file name=fff onchange=aa();> 
</form>

</body> 
</html>

<script> 
function aa(){ 
if(document.aaa.fff.value != ""){ 
document.aaa.action = "test4.php"; 
document.aaa.submit(); 
} 
} 
</script>