function checkKeyword() {
	var field = window.document.ricerca.keyword;
	if (field.value == "") {
		alert('Inserire la parola chiave!');
		field.focus();
		return (false);
	} else if (field.value.length < 4) {
		alert('La parola chiave deve essere costituita da almeno 4 caratteri!');
		field.focus();
		return (false);
	} else {
		return (true);
	}
}

function rolloverCat(obj) {
	obj.style.backgroundColor = '#EEEEEE';
}

function rolloutCat(obj) {
	obj.style.backgroundColor = '';
}

function setAlpha(obj, currentAlpha) {
	obj.style.filter = 'Alpha(Opacity='+currentAlpha+')';
}

function emailCheck(emailStr) {
	var checkTLD = 1;
	var knownDomsPat = /^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
	var emailPat = /^(.+)@(.+)$/;
	var specialChars = "\\(\\)><@,;:\\\\\\\"\\.\\[\\]";
	var validChars = "\[^\\s" + specialChars + "\]";
	var quotedUser = "(\"[^\"]*\")";
	var ipDomainPat = /^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
	var atom = validChars + '+';
	var word = "(" + atom + "|" + quotedUser + ")";
	var userPat = new RegExp("^" + word + "(\\." + word + ")*$");
	var domainPat = new RegExp("^" + atom + "(\\." + atom +")*$");
	var matchArray = emailStr.match(emailPat);
	if (matchArray == null) {
		// alert("Email address seems incorrect (check @ and .'s)");
		return false;
	}
	var user = matchArray[1];
	var domain = matchArray[2];
	for (i=0; i < user.length; i++) {
		if (user.charCodeAt(i) > 127) {
			// alert("Ths username contains invalid characters.");
			return false;
   		}
	}
	for (i=0; i < domain.length; i++) {
		if (domain.charCodeAt(i) > 127) {
			// alert("Ths domain name contains invalid characters.");
			return false;
		}
	}
	if (user.match(userPat) == null) {
		// alert("The username doesn't seem to be valid.");
		return false;
	}
	var IPArray = domain.match(ipDomainPat);
	if (IPArray != null) {
		for (var i=1; i <= 4; i++) {
			if (IPArray[i] > 255) {
				// alert("Destination IP address is invalid!");
				return false;
		   }
		}
		return true;
	}
	var atomPat = new RegExp("^" + atom + "$");
	var domArr = domain.split(".");
	var len = domArr.length;
	for (i = 0; i < len; i++) {
		if (domArr[i].search(atomPat) == -1) {
			// alert("The domain name does not seem to be valid.");
			return false;
	   }
	}
	/*
	if (checkTLD && domArr[domArr.length-1].length != 2 && domArr[domArr.length-1].search(knownDomsPat) == -1) {
		// alert("The address must end in a well-known domain or two letter " + "country.");
		return false;
	}
	*/
	if (len < 2) {
		// alert("This address is missing a hostname!");
		return false;
	}
	return true;
}

function changeEvidence(frame_selected) {
	clearInterval(evidenceRollID);
	for (var frame_counter = 0; frame_counter <= 5; frame_counter++) {
		if (document.getElementById('evidence_frame_'+frame_counter)) {
			document.getElementById('evidence_frame_'+frame_counter).style.display = 'none';
			document.getElementById('evidence_link_'+frame_counter).style.display = 'none';
			document.getElementById('evidence_number_'+frame_counter).setAttribute('class', 'page');
			document.getElementById('evidence_number_'+frame_counter).className = 'page';
		}
	}
	if (document.getElementById('evidence_frame_'+frame_selected)) {
		document.getElementById('evidence_frame_'+frame_selected).style.display = 'block';
		document.getElementById('evidence_link_'+frame_selected).style.display = 'block';
		document.getElementById('evidence_number_'+frame_selected).setAttribute('class', 'page_selected');
		document.getElementById('evidence_number_'+frame_selected).className = 'page_selected';
	}
}

function showDropdown(obj_id) {
	if (document.getElementById(obj_id)) {
		document.getElementById(obj_id).style.display = 'block';
	}
}

function hideDropdown(obj_id) {
	if (document.getElementById(obj_id)) {
		document.getElementById(obj_id).style.display = 'none';
	}
}

function rolloverDropdown(obj) {
	obj.style.backgroundColor = '#000000';
}

function rolloutDropdown(obj) {
	obj.style.backgroundColor = '';
}