//Retorna: 1 = NIF ok, 2 = CIF ok, 3 = NIE ok, -1 = NIF error, -2 = CIF error, -3 = NIE error, 0 = ??? error
function valida_nif_cif_nie(a)
{

var temp=a.toUpperCase();
var cadenadni='TRWAGMYFPDXBNJZSQVHLCKE';
if (temp!==''){

//si no tiene un formato valido devuelve error
if ((!/^[A-Z]{1}[0-9]{7}[A-Z0-9]{1}$/.test(temp) && !/^[T]{1}[A-Z0-9]{8}$/.test(temp)) && !/^[0-9]{8}[A-Z]{1}$/.test(temp))
{
return 0;
}

//comprobacion de NIFs estandar
if (/^[0-9]{8}[A-Z]{1}$/.test(temp))
{
posicion = a.substring(8,0) % 23;
letra = cadenadni.charAt(posicion);
var letradni=temp.charAt(8);
if (letra == letradni)
{
return 1;
}
else
{
return -1;
}
}

//algoritmo para comprobacion de codigos tipo CIF
suma = parseInt(a.charAt(2))+parseInt(a.charAt(4))+parseInt(a.charAt(6));

for (i = 1; i < 8; i += 2)
{
temp1 = 2 * parseInt(a.charAt(i));
temp1 += '';
temp1 = temp1.substring(0,1);
temp2 = 2 * parseInt(a.charAt(i));
temp2 += '';
temp2 = temp2.substring(1,2);
if (temp2 == '')
{
temp2 = '0';
}

suma += (parseInt(temp1) + parseInt(temp2));
}
suma += '';
n = 10 - parseInt(suma.substring(suma.length-1, suma.length));

//comprobacion de NIFs especiales (se calculan como CIFs)
if (/^[KLM]{1}/.test(temp))
{
if (a.charAt(8) == String.fromCharCode(64 + n))
{
return 1;
}
else
{
return -1;
}
}
//comprobacion de CIFs
if (/^[ABCDEFGHJNPQRSUVW]{1}/.test(temp))
{
temp = n + '';
if (a.charAt(8) == String.fromCharCode(64 + n) || a.charAt(8) == parseInt(temp.substring(temp.length-1, temp.length)))
{
return 2;
}
else
{
return -2;
}
}

//comprobacion de NIEs
//T
if (/^[T]{1}[A-Z0-9]{8}$/.test(temp))
{
if (a.charAt(8) == /^[T]{1}[A-Z0-9]{8}$/.test(temp))
{
return 3;
}
else
{
return -3;
}
}

//XYZ
if (/^[XYZ]{1}/.test(temp))
{

temp = temp.replace('X','0')
temp = temp.replace('Y','1')
temp = temp.replace('Z','2')
pos = str_replace(['X', 'Y', 'Z'], 0, ['0','1','2'], temp).substring(0, 8) % 23;

if (a.charAt(8) == cadenadni.substring(pos, pos + 1))
{
return 3;
}
else
{
return -3;
}
}
}
return 0;
}


//function str_replace(search, position, replace, subject) {
//var f = search, r = replace, s = subject, p = position;
//var ra = r instanceof Array, sa = s instanceof Array, f = [].concat(f), r = [].concat(r), i = (s = [].concat(s)).length;
//while (j = 0, i-) {
//if (s[i]) {
//while (s[p] = s[p].split(f[j]).join(ra ? r[j] || '' : r[0]), ++j in f){};
//}
//};
//return sa ? s : s[0];
//}

function str_replace (search, count, replace, subject) {
	var i = 0, j = 0, temp = '', repl = '', sl = 0, fl = 0,
            f = [].concat(search),
            r = [].concat(replace),
            s = subject,
            ra = r instanceof Array, sa = s instanceof Array;    s = [].concat(s);
    if (count) {
        this.window[count] = 0;
    }
     for (i=0, sl=s.length; i < sl; i++) {
        if (s[i] === '') {
            continue;
        }
        for (j=0, fl=f.length; j < fl; j++) {            temp = s[i]+'';
            repl = ra ? (r[j] !== undefined ? r[j] : '') : r[0];
            s[i] = (temp).split(f[j]).join(repl);
            if (count && s[i] !== temp) {
                this.window[count] += (temp.length-s[i].length)/f[j].length;}        }
    }
    return sa ? s : s[0];
}