Request: field drop-down list with conditional

Let me explain briefly what I need .. I have two fields in the drop down menu:
The first called “Job type” that consists of Option 1 Option 2 and Option 3
The second called “Use Current” which is composed of Option A Option B Option C

I would have opted to create fields named X in the same way with the various lists .. but it does not seem appropriate to create too much work for the server as some options are shared .. type

If I choose the first option field 1 -> com comes out in the second option A and option B and option C
If I choose the first option field 2 -> the field is out in the world according Option A and Option C
etc. etc.
But I would just be able to create only one field and gradually influence the various lists according to selta of the first field. This to me would be more useful ..

I go on the internet a thing that I want to do .. I found this java source code.

<script type='text/javascript'>
var totale_professioni = 57;
a = new Array(57);
a[0]= new Array(3);a[0][0]=2;a[0][1]=4;a[0][2]='Impiegato';
a[1]= new Array(3);a[1][0]=1;a[1][1]=2;a[1][2]='Contratto di inserimento';
a[2]= new Array(3);a[2][0]=3;a[2][1]=14;a[2][2]='Architetto';
a[3]= new Array(3);a[3][0]=7;a[3][1]=29;a[3][2]='Pensione di anzianità';
a[4]= new Array(3);a[4][0]=8;a[4][1]=30;a[4][2]='Disoccupato';
a[5]= new Array(3);a[5][0]=9;a[5][1]=44;a[5][2]='Agente di Assicurazione';
a[6]= new Array(3);a[6][0]=4;a[6][1]=25;a[6][2]='Reddito non dimostrabile';
a[7]= new Array(3);a[7][0]=5;a[7][1]=26;a[7][2]='Studente';
a[8]= new Array(3);a[8][0]=6;a[8][1]=27;a[8][2]='Casalinga';
a[9]= new Array(3);a[9][0]=10;a[9][1]=57;a[9][2]='Militare di leva';
a[10]= new Array(3);a[10][0]=11;a[10][1]=58;a[10][2]='Cassintegrato';
a[11]= new Array(3);a[11][0]=9;a[11][1]=22;a[11][2]='Rappresentante/Agente';
a[12]= new Array(3);a[12][0]=7;a[12][1]=28;a[12][2]='Pensione sociale';
a[13]= new Array(3);a[13][0]=3;a[13][1]=15;a[13][2]='Avvocato';
a[14]= new Array(3);a[14][0]=1;a[14][1]=1;a[14][2]='Apprendista';
a[15]= new Array(3);a[15][0]=2;a[15][1]=5;a[15][2]='Quadro';
a[16]= new Array(3);a[16][0]=2;a[16][1]=3;a[16][2]='Operaio';
a[17]= new Array(3);a[17][0]=3;a[17][1]=16;a[17][2]='Commercialista';
a[18]= new Array(3);a[18][0]=9;a[18][1]=45;a[18][2]='Ambulante';
a[19]= new Array(3);a[19][0]=1;a[19][1]=31;a[19][2]='Insegnante non di ruolo';
a[20]= new Array(3);a[20][0]=2;a[20][1]=32;a[20][2]='Operaio specializzato';
a[21]= new Array(3);a[21][0]=9;a[21][1]=46;a[21][2]='Artista';
a[22]= new Array(3);a[22][0]=3;a[22][1]=17;a[22][2]='Ingegnere';
a[23]= new Array(3);a[23][0]=3;a[23][1]=18;a[23][2]='Medico';
a[24]= new Array(3);a[24][0]=2;a[24][1]=6;a[24][2]='Dirigente';
a[25]= new Array(3);a[25][0]=9;a[25][1]=23;a[25][2]='Autotrasportatore';
a[26]= new Array(3);a[26][0]=9;a[26][1]=21;a[26][2]='Artigiano';
a[27]= new Array(3);a[27][0]=2;a[27][1]=8;a[27][2]='Docente universitario';
a[28]= new Array(3);a[28][0]=3;a[28][1]=19;a[28][2]='Notaio';
a[29]= new Array(3);a[29][0]=2;a[29][1]=7;a[29][2]='Insegnante di ruolo';
a[30]= new Array(3);a[30][0]=9;a[30][1]=47;a[30][2]='Agricoltore/allevatore';
a[31]= new Array(3);a[31][0]=9;a[31][1]=48;a[31][2]='Consulente';
a[32]= new Array(3);a[32][0]=2;a[32][1]=11;a[32][2]='Medico ospedaliero';
a[33]= new Array(3);a[33][0]=2;a[33][1]=10;a[33][2]='Personale paramedico';
a[34]= new Array(3);a[34][0]=9;a[34][1]=49;a[34][2]='Collaboratrice domestica';
a[35]= new Array(3);a[35][0]=2;a[35][1]=33;a[35][2]='Infermiere/a';
a[36]= new Array(3);a[36][0]=9;a[36][1]=20;a[36][2]='Commerciante';
a[37]= new Array(3);a[37][0]=2;a[37][1]=34;a[37][2]='Magistrato';
a[38]= new Array(3);a[38][0]=9;a[38][1]=50;a[38][2]='Geometra';
a[39]= new Array(3);a[39][0]=2;a[39][1]=12;a[39][2]='Militare/Ufficiale';
a[40]= new Array(3);a[40][0]=9;a[40][1]=24;a[40][2]='Imprenditore';
a[41]= new Array(3);a[41][0]=9;a[41][1]=51;a[41][2]='Lavoratore a domicilio';
a[42]= new Array(3);a[42][0]=2;a[42][1]=35;a[42][2]='Militare/Sottufficiale';
a[43]= new Array(3);a[43][0]=2;a[43][1]=36;a[43][2]='Militare/Altro';
a[44]= new Array(3);a[44][0]=9;a[44][1]=52;a[44][2]='Perito';
a[45]= new Array(3);a[45][0]=9;a[45][1]=53;a[45][2]='Promotore finanziario';
a[46]= new Array(3);a[46][0]=2;a[46][1]=37;a[46][2]='Addetto P.S.';
a[47]= new Array(3);a[47][0]=2;a[47][1]=38;a[47][2]='Vigile Urbano';
a[48]= new Array(3);a[48][0]=9;a[48][1]=54;a[48][2]='Ragioniere';
a[49]= new Array(3);a[49][0]=9;a[49][1]=55;a[49][2]='Socio di società';
a[50]= new Array(3);a[50][0]=2;a[50][1]=39;a[50][2]='Vigile del Fuoco';
a[51]= new Array(3);a[51][0]=9;a[51][1]=56;a[51][2]='Sportivo professionista';
a[52]= new Array(3);a[52][0]=2;a[52][1]=9;a[52][2]='Autista';
a[53]= new Array(3);a[53][0]=2;a[53][1]=13;a[53][2]='Barista/Cameriere/Etc.';
a[54]= new Array(3);a[54][0]=2;a[54][1]=40;a[54][2]='Manovale';
a[55]= new Array(3);a[55][0]=2;a[55][1]=41;a[55][2]='Commesso/a';
a[56]= new Array(3);a[56][0]=2;a[56][1]=42;a[56][2]='Portiere';
a[57]= new Array(3);a[57][0]=2;a[57][1]=43;a[57][2]='Ecclesiastico';
</script>

l’esempio pratico lo trovate a questo http://www.prestitionline.it/personali/

https://wordpress.org/plugins/caldera-forms/