Hola
blas9
A ver si es esto lo que necesitas:
Código PHP:
<html>
<head>
<script type="text/javascript">
function validar(frm) {
if (frm.sel.selectedIndex == -1 || frm.archi.value=='')
return false;
}
</script>
</head>
<body>
<form action="javascript:alert('si')" onsubmit="return validar(this)">
<select name="sel" size="5" multiple>
<option>Uno</option>
<option>Dos</option>
<option>Tres</option>
</select>
<input type="file" name="archi" />
<input type="submit" />
</form>
</body>
</html>
Saludos,
