ho il seguente codice:
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />



<style type="text/css">
@import url("emptystyle.css");
a#viewcss{color: #00f;font-weight: bold}
</style>


<script type="text/javascript">
function avanti(val) {
document.form1.azione.value="avanti";
document.form1.submit();

}
function indietro(val) {

document.form1.azione.value="indietro";
document.form1.submit();

}
function collegamento(valore) {

document.form1.frame.value=0;
document.form1.galleria.value=valore;
document.form1.submit();

}
function popup(valore,width,height)
{

document.form1.galleriadett.value=valore;
window.open('Dettaglio.php?galleriadett='+valore,' ','width ='+width+',height='+height+',left=1,top=1 scrollbars=0');
//this.form1.action="Dettaglio.php";

//this.form1.target="_blank";
//this.form1.submit();


}
</script>
</head>


l'errore di validazione del w3c è:
Line 50, column 7: end tag for "head" which is not finished

</head>

Most likely, You nested tags and closed them in the wrong order. For example

[i]...</p> is not acceptable, as [i] must be closed before

. Acceptable nesting is:

...</p>

Another possibility is that you used an element (e.g. 'ul') which requires a child element (e.g. 'li') that you did not include. Hence the parent element is "not finished", not complete.

non capisco cosa c'è da cambiare!! premetto che ho cercato ma nisba.
mi aiutate?
grazie ciao