<span>Номер отделения</span>
<input  type="text" required  size="90px" id="departament" oninput="input()">
<span>Адрес отделения</span>
<input  type="text" required  size="90px" id="address" disabled>

var dep_address=new Array();
        dep_address[0]=1;
        dep_address[1]="address 1 departament";
        dep_address[2]=2;
        dep_address[3]="address 2 departament";
        dep_address[4]=3;
        dep_address[5]="address 3 departament";
        dep_address[6]=4;
        dep_address[7]="address 4 departament";
        dep_address[8]=5;
        dep_address[9]="address 5 departament";