JSFiddle - React, Tailwind, and code Playground

HTML

<body onload="TabNumbers()">
        <div class="a">
            <div id="Div01">
                <p>Div 01</p>
                <input id="Div01Field1" type="text" value="Me first"/>
                <div>
                  <input id="Div01Field1" type="text" value="Me second"/>
                  <input id="Div01Field3" type="text" value="Me third"/>
                </div>
                <hr>
            </div>
            <div id="Div03">
                <p>Div 03</p>
                <input id="Div03Field1" type="text" value="Me seventh"/>
                <input id="Div03Field2" type="text" value="Me eighth"/>
                <input id="Div03Field3" type="text" value="Me ninth"/>
                <hr>
            </div>
            <div id="Div05">
                <p>Div 05</p>
                <input id="Div05Field1" type="text" value="Me thirteenth"/>
                <input id="Div05Field2" type="text" value="Me fourteenth"/>
                <input id="Div05Field3" type="text" value="Me fifteenth"/>
            </div>
        </div>
        <div class="a">
            <div id="Div02">
                <p>Div 02</p>
                <input id="Div02Field1" type="text" value="Me fourth"/>
                <input id="Div02Field2" type="text" value="Me fifth"/>
                <input id="Div02Field3" type="text" value="Me sixth"/>
                <hr>
            </div>
            <div id="Div04">
                <p>Div 04</p>
                <input id="Div04Field1" type="text" value="Me tenth"/>
                <input id="Div04Field2" type="text" value="Me eleventh"/>
                <input id="Div04Field3" type="text" value="Me twelfth"/>
                <hr>
            </div>
            <div id="Div06">
                <p>Div 06</p>
                <input id="Div06Field1" type="text" value="Me sixteenth"/>
                <input id="Div06Field2" type="text" value="Me seventeenth"/>
                <input id="Div06Field3" type="text" value="Me eighteenth"/>
      ...

CSS

.a { display: inline-block;
     width:200px;
     border: 1px solid black;
}

JavaScript

function TabNumbers() { var t = document.getElementById('Div01').childNodes;
                        for(i=0; i<t.length; i++) { if (t[i].tagName == 'INPUT' || t[i].tagName == 'SELECT' || t[i].tagName == 'BUTTON') t[i].tabIndex = 1;
                        }
                        var t = document.getElementById('Div02').childNodes;
                        for(i=0; i<t.length; i++) { if (t[i].tagName == 'INPUT' || t[i].tagName == 'SELECT' || t[i].tagName == 'BUTTON') t[i].tabIndex = 2;
                        }
                        var t = document.getElementById('Div03').childNodes;
                        for(i=0; i<t.length; i++) { if (t[i].tagName == 'INPUT' || t[i].tagName == 'SELECT' || t[i].tagName == 'BUTTON') t[i].tabIndex = 3;
                        }
                        var t = document.getElementById('Div04').childNodes;
                        for(i=0; i<t.length; i++) { if (t[i].tagName == 'INPUT' || t[i].tagName == 'SELECT' || t[i].tagName == 'BUTTON') t[i].tabIndex = 4;
                        }
                        var t = document.getElementById('Div05').childNodes;
                        for(i=0; i<t.length; i++) { if (t[i].tagName == 'INPUT' || t[i].tagName == 'SELECT' || t[i].tagName == 'BUTTON') t[i].tabIndex = 5;
                        }
                        var t = document.getElementById('Div06').childNodes;
                        for(i=0; i<t.length; i++) { if (t[i].tagName == 'INPUT' || t[i].tagName == 'SELECT' || t[i].tagName == 'BUTTON') t[i].tabIndex = 6;
                        }
}