Salve, ho fatto la pratica e non funziona..
Mi dite perchè?

Ecco il codice.

<script>

function inserisci()
{

document.file_upload_form.onsubmit = function()
{

document.getElementById("file_upload_form").target = 'upload_target';
document.getElementById("file_upload_form").submit ();

}

}



</script>
<form id="file_upload_form" name="file_upload_form" method="post" enctype="multipart/form-data">
<input name="datafile" id="datafile" size="27" type="file" />

<input type="button" name="action" value="Upload" onClick="inserisci();" />

<iframe id="upload_target" name="upload_target" src="ipload.php" style="width:0;height:0;border:0px solid #fff;"></iframe>
</form>

INOLTRE HO PROVATO ANCHE COSI'

<script>

function inserisci()
{

document.file_upload_form.onsubmit = function()
{

document.getElementById("file_upload_form").target = 'upload_target';
document.getElementById("file_upload_form").action = 'ipload.php';
document.getElementById("file_upload_form").submit ();

}

}



</script>
<form id="file_upload_form" name="file_upload_form" method="post" enctype="multipart/form-data">
<input name="datafile" id="datafile" size="27" type="file" />

<input type="button" name="action" value="Upload" onClick="inserisci();" />

<iframe id="upload_target" name="upload_target" src="" style="width:0;height:0;border:0px solid #fff;"></iframe>
</form>

E non funziona neanche così...
:-(