function checkSpecialChar (oForm)	
{
	oForm.didascalia.value = oForm.didascalia.value.replace (/'/g, "'");
	oForm.didascalia.value = oForm.didascalia.value.replace  (/’/g, "’");
	oForm.didascalia.value = oForm.didascalia.value.replace  (/ä/g, "ä");
	oForm.didascalia.value = oForm.didascalia.value.replace  (/\"/g, """);
	oForm.didascalia.value = oForm.didascalia.value.replace  (/à/g, "à");
	oForm.didascalia.value = oForm.didascalia.value.replace  (/è/g, "è");
	oForm.didascalia.value = oForm.didascalia.value.replace  (/é/g, "é");
	oForm.didascalia.value = oForm.didascalia.value.replace  (/ì/g, "ì");
	oForm.didascalia.value = oForm.didascalia.value.replace  (/ò/g, "ò");
	oForm.didascalia.value = oForm.didascalia.value.replace  (/ù/g, "ù");
	oForm.didascalia.value = oForm.didascalia.value.replace  (/\r\n/g, "<br>");
	oForm.didascalia.value = oForm.didascalia.value.replace  (/:/g, "&#58;");
	oForm.didascalia.value = oForm.didascalia.value.replace  (/\\/g, "");
	return true;
}
 
function changeImg(sImgName, sImgSrc)
{
	document[sImgName].src= "images/" + sImgSrc;
}

function checkRequired(oField, sAlertTxt)
{
	with (oField)
	{
		if (value == null || value == "")
  		{
			alert(sAlertTxt);
			return false;
		}
		else 
		{
			return true;
		}
	}
}

function checkForm(oForm)
{
	with (oForm)
	{
		if (checkRequired(user, "Compilare il campo 'User'") == false)
  		{
			user.focus();
			return false;
		}
		if (checkRequired(pwd, "Compilare il campo 'Pwd'") == false)
  		{
			pwd.focus();
			return false;
		}
		else
		{
			chk.value = hex_sha1(pwd.value);		
		}
	}
}

function checkComment(oForm)
{
	with (oForm)
	{
		if (checkRequired(nickname, "Compilare il campo 'Nick'") == false)
  		{
			nickname.focus();
			return false;
		}
		if (checkRequired(mail, "Compilare il campo 'Mail'") == false)
  		{
			mail.focus();
			return false;
		}
		if (emailCheck(mail.value) == false)
		{
			alert("Correggere il campo 'Mail'");
			mail.focus();
			return false;
		}
		if (checkRequired(commento, "Compilare il campo 'Commento'") == false)
  		{
			commento.focus();
			return false;
		}
	}
}

function emailCheck (emailStr) {
	/* The following pattern is used to check if the entered e-mail address
	   fits the user@domain format.  It also is used to separate the username
	   from the domain. */
	var emailPat=/^(.+)@(.+)$/
	/* The following string represents the pattern for matching all special
	   characters.  We don't want to allow special characters in the address. 
	   These characters include ( ) < > @ , ; : \ " . [ ]    */
	var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
	/* The following string represents the range of characters allowed in a 
	   username or domainname.  It really states which chars aren't allowed. */
	var validChars="\[^\\s" + specialChars + "\]"
	/* The following pattern applies if the "user" is a quoted string (in
	   which case, there are no rules about which characters are allowed
	   and which aren't; anything goes).  E.g. "jiminy cricket"@disney.com
	   is a legal e-mail address. */
	var quotedUser="(\"[^\"]*\")"
	/* The following pattern applies for domains that are IP addresses,
	   rather than symbolic names.  E.g. joe@[123.124.233.4] is a legal
	   e-mail address. NOTE: The square brackets are required. */
	var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
	/* The following string represents an atom (basically a series of
	   non-special characters.) */
	var atom=validChars + '+'
	/* The following string represents one word in the typical username.
	   For example, in john.doe@somewhere.com, john and doe are words.
	   Basically, a word is either an atom or quoted string. */
	var word="(" + atom + "|" + quotedUser + ")"
	// The following pattern describes the structure of the user
	var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
	/* The following pattern describes the structure of a normal symbolic
	   domain, as opposed to ipDomainPat, shown above. */
	var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")
	
	
	/* Finally, let's start trying to figure out if the supplied address is
	   valid. */
	
	/* Begin with the coarse pattern to simply break up user@domain into
	   different pieces that are easy to analyze. */
	var matchArray=emailStr.match(emailPat)
	if (matchArray==null) {
	  /* Too many/few @'s or something; basically, this address doesn't
	     even fit the general mould of a valid e-mail address. */
		//alert("Email address seems incorrect (check @ and .'s)")
		return false
	}
	var user=matchArray[1]
	var domain=matchArray[2]
	
	// See if "user" is valid 
	if (user.match(userPat)==null) {
	    // user is not valid
	    //alert("The username doesn't seem to be valid.")
	    return false
	}
	
	/* if the e-mail address is at an IP address (as opposed to a symbolic
	   host name) make sure the IP address is valid. */
	var IPArray=domain.match(ipDomainPat)
	if (IPArray!=null) {
	    // this is an IP address
		  for (var i=1;i<=4;i++) {
		    if (IPArray[i]>255) {
		        //alert("Destination IP address is invalid!")
			return false
		    }
	    }
	    return true
	}
	
	// Domain is symbolic name
	var domainArray=domain.match(domainPat)
	if (domainArray==null) {
		//alert("The domain name doesn't seem to be valid.")
	    return false
	}
	
	/* domain name seems valid, but now make sure that it ends in a
	   three-letter word (like com, edu, gov) or a two-letter word,
	   representing country (uk, nl), and that there's a hostname preceding 
	   the domain or country. */
	
	/* Now we need to break up the domain to get a count of how many atoms
	   it consists of. */
	var atomPat=new RegExp(atom,"g")
	var domArr=domain.match(atomPat)
	var len=domArr.length
	if (domArr[domArr.length-1].length<2 || 
	    domArr[domArr.length-1].length>3) {
	   // the address must end in a two letter or three letter word.
	   //alert("The address must end in a three-letter domain, or two letter country.")
	   return false
	}
	
	// Make sure there's a host name preceding the domain.
	if (len<2) {
	   var errStr="This address is missing a hostname!"
	   //alert(errStr)
	   return false
	}
	
	// If we've gotten this far, everything's valid!
	return true;
}

/*
 * A JavaScript implementation of the Secure Hash Algorithm, SHA-1, as defined
 * in FIPS PUB 180-1
 * Version 2.1a Copyright Paul Johnston 2000 - 2002.
 * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
 * Distributed under the BSD License
 * See http://pajhome.org.uk/crypt/md5 for details.
 */

/*
 * Configurable variables. You may need to tweak these to be compatible with
 * the server-side, but the defaults work in most cases.
 */
var hexcase = 0;  /* hex output format. 0 - lowercase; 1 - uppercase        */
var b64pad  = ""; /* base-64 pad character. "=" for strict RFC compliance   */
var chrsz   = 8;  /* bits per input character. 8 - ASCII; 16 - Unicode      */

/*
 * These are the functions you'll usually want to call
 * They take string arguments and return either hex or base-64 encoded strings
 */
function hex_sha1(s){return binb2hex(core_sha1(str2binb(s),s.length * chrsz));}
function b64_sha1(s){return binb2b64(core_sha1(str2binb(s),s.length * chrsz));}
function str_sha1(s){return binb2str(core_sha1(str2binb(s),s.length * chrsz));}
function hex_hmac_sha1(key, data){ return binb2hex(core_hmac_sha1(key, data));}
function b64_hmac_sha1(key, data){ return binb2b64(core_hmac_sha1(key, data));}
function str_hmac_sha1(key, data){ return binb2str(core_hmac_sha1(key, data));}

/*
 * Perform a simple self-test to see if the VM is working
 */
function sha1_vm_test()
{
  return hex_sha1("abc") == "a9993e364706816aba3e25717850c26c9cd0d89d";
}

/*
 * Calculate the SHA-1 of an array of big-endian words, and a bit length
 */
function core_sha1(x, len)
{
  /* append padding */
  x[len >> 5] |= 0x80 << (24 - len % 32);
  x[((len + 64 >> 9) << 4) + 15] = len;

  var w = Array(80);
  var a =  1732584193;
  var b = -271733879;
  var c = -1732584194;
  var d =  271733878;
  var e = -1009589776;

  for(var i = 0; i < x.length; i += 16)
  {
    var olda = a;
    var oldb = b;
    var oldc = c;
    var oldd = d;
    var olde = e;

    for(var j = 0; j < 80; j++)
    {
      if(j < 16) w[j] = x[i + j];
      else w[j] = rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);
      var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)),
                       safe_add(safe_add(e, w[j]), sha1_kt(j)));
      e = d;
      d = c;
      c = rol(b, 30);
      b = a;
      a = t;
    }

    a = safe_add(a, olda);
    b = safe_add(b, oldb);
    c = safe_add(c, oldc);
    d = safe_add(d, oldd);
    e = safe_add(e, olde);
  }
  return Array(a, b, c, d, e);

}

/*
 * Perform the appropriate triplet combination function for the current
 * iteration
 */
function sha1_ft(t, b, c, d)
{
  if(t < 20) return (b & c) | ((~b) & d);
  if(t < 40) return b ^ c ^ d;
  if(t < 60) return (b & c) | (b & d) | (c & d);
  return b ^ c ^ d;
}

/*
 * Determine the appropriate additive constant for the current iteration
 */
function sha1_kt(t)
{
  return (t < 20) ?  1518500249 : (t < 40) ?  1859775393 :
         (t < 60) ? -1894007588 : -899497514;
}

/*
 * Calculate the HMAC-SHA1 of a key and some data
 */
function core_hmac_sha1(key, data)
{
  var bkey = str2binb(key);
  if(bkey.length > 16) bkey = core_sha1(bkey, key.length * chrsz);

  var ipad = Array(16), opad = Array(16);
  for(var i = 0; i < 16; i++)
  {
    ipad[i] = bkey[i] ^ 0x36363636;
    opad[i] = bkey[i] ^ 0x5C5C5C5C;
  }

  var hash = core_sha1(ipad.concat(str2binb(data)), 512 + data.length * chrsz);
  return core_sha1(opad.concat(hash), 512 + 160);
}

/*
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally
 * to work around bugs in some JS interpreters.
 */
function safe_add(x, y)
{
  var lsw = (x & 0xFFFF) + (y & 0xFFFF);
  var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
  return (msw << 16) | (lsw & 0xFFFF);
}

/*
 * Bitwise rotate a 32-bit number to the left.
 */
function rol(num, cnt)
{
  return (num << cnt) | (num >>> (32 - cnt));
}

/*
 * Convert an 8-bit or 16-bit string to an array of big-endian words
 * In 8-bit function, characters >255 have their hi-byte silently ignored.
 */
function str2binb(str)
{
  var bin = Array();
  var mask = (1 << chrsz) - 1;
  for(var i = 0; i < str.length * chrsz; i += chrsz)
    bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (32 - chrsz - i%32);
  return bin;
}

/*
 * Convert an array of big-endian words to a string
 */
function binb2str(bin)
{
  var str = "";
  var mask = (1 << chrsz) - 1;
  for(var i = 0; i < bin.length * 32; i += chrsz)
    str += String.fromCharCode((bin[i>>5] >>> (32 - chrsz - i%32)) & mask);
  return str;
}

/*
 * Convert an array of big-endian words to a hex string.
 */
function binb2hex(binarray)
{
  var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
  var str = "";
  for(var i = 0; i < binarray.length * 4; i++)
  {
    str += hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8+4)) & 0xF) +
           hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8  )) & 0xF);
  }
  return str;
}

/*
 * Convert an array of big-endian words to a base-64 string
 */
function binb2b64(binarray)
{
  var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  var str = "";
  for(var i = 0; i < binarray.length * 4; i += 3)
  {
    var triplet = (((binarray[i   >> 2] >> 8 * (3 -  i   %4)) & 0xFF) << 16)
                | (((binarray[i+1 >> 2] >> 8 * (3 - (i+1)%4)) & 0xFF) << 8 )
                |  ((binarray[i+2 >> 2] >> 8 * (3 - (i+2)%4)) & 0xFF);
    for(var j = 0; j < 4; j++)
    {
      if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;
      else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);
    }
  }
  return str;
}

function isInteger(s){
	var i;
    for (i = 0; i < s.length; i++){   
        // Check that current character is number.
        var c = s.charAt(i);
        if (((c < "0") || (c > "9"))) return false;
    }
    // All characters are numbers.
    return true;
}

function stripCharsInBag(s, bag){
	var i;
    var returnString = "";
    // Search through string's characters one by one.
    // If character is not in bag, append to returnString.
    for (i = 0; i < s.length; i++){   
        var c = s.charAt(i);
        if (bag.indexOf(c) == -1) returnString += c;
    }
    return returnString;
}

/*
 * Check the date inserted by the user
 */
function daysInFebruary (year)
{
	// February has 29 days in any year evenly divisible by four,
    // EXCEPT for centurial years which are not also divisible by 400.
    return (((year % 4 == 0) && ( (!(year % 100 == 0)) || (year % 400 == 0))) ? 29 : 28 );
}
function DaysArray(n) 
{
	for (var i = 1; i <= n; i++) 
	{
		this[i] = 31;
		if (i == 4 || i == 6 || i == 9 || i == 11) { this[i] = 30; }
		if (i == 2) { this[i] = 29; }
   	} 
   	return this;
}

function isDate(dtStr)
{
	var dtCh= "/";
	var minYear=2006;
	var maxYear=2100;
	var daysInMonth = DaysArray(12);
	var pos1 = dtStr.indexOf(dtCh);
	var pos2 = dtStr.indexOf(dtCh, pos1 + 1);
	var strDay = dtStr.substring(0, pos1);
	var strMonth = dtStr.substring(pos1 + 1, pos2);
	var strYear = dtStr.substring(pos2 + 1);
	strYr = strYear;
	if (strDay.charAt(0)=="0" && strDay.length>1)
	{
		strDay = strDay.substring(1);	
	} 
	if (strMonth.charAt(0) == "0" && strMonth.length > 1)
	{
	 	strMonth=strMonth.substring(1);
	}
	for (var i = 1; i <= 3; i++) 
	{
		if (strYr.charAt(0) == "0" && strYr.length > 1)
		{
			strYr = strYr.substring(1);
		} 
	}
	month = parseInt(strMonth);
	day = parseInt(strDay);
	year = parseInt(strYr);
	
	if (pos1 == -1 || pos2 == -1)
	{
		alert("Il formato della data deve essere : gg/mm/aaaa");
		return false;
	}
	if (strMonth.length < 1 || month < 1 || month > 12)
	{
		alert("Inserisci un mese valido");
		return false;
	}
	if (strDay.length < 1 || day < 1 || day > 31 || (month == 2 && day > daysInFebruary (year)) || day > daysInMonth[month])
	{
		alert("Inserisci un giorno valido");
		return false;
	}
	if (strYear.length != 4 || year == 0 || year < minYear || year > maxYear)
	{
		alert("Inserisci un anno valido nel formato aaaa");
		return false;
	}
	if (dtStr.indexOf(dtCh, pos2 + 1)!= -1 || isInteger(stripCharsInBag(dtStr, dtCh)) == false)
	{
		alert("Inserisci una data valida");
		return false;
	}
	return true;
}

function checkFolder(oForm)
{
	with (oForm)
	{
		if (checkRequired(cartella, "Compilare il campo 'Cartella'") == false)
  		{
			cartella.focus();
			return false;
		}
		if (checkRequired(data, "Compilare il campo 'Data'") == false)
  		{
			data.focus();
			return false;
		}
		if (isDate(data.value)==false)
		{
			data.focus();
			return false;
		}
	}
}