[js] controllo tipo file upload

[br1]

<script>
var rv=false;
function preload(fil) {
// controllo il tipo di file
	ok = false;
	ext = fil.substr(fil.lastIndexOf("."))+".";
	perm = ".jpg.gif.png."
	if(perm.indexOf(ext.toLowerCase())<0){
		alert("File non consentito");
//		document.myFrm.reset();
		rv = false;
	} else {
		rv = true;
	}
}
</script>
...
<form name="myFrm" onsubmit="return rv;">
<input type="file" size=40 name="myFile"
	onchange="preload(this.value)">
</form>

ciao