JSFiddle - React, Tailwind, and code Playground

HTML

<select id="block1">     
    <option value="0">Item 0</option>
    <option value="111">Item 1</option>
    <option value="112">Item 2</option>
    <option value="113">Item 3</option>
    <option value="114">Item 4</option>
    <option value="115">Item 5</option>
    <option value="116">Item 6</option>
    <option value="117">Item 7</option>
</select>
<select id="block2">     
    <option value="0">Item 0</option>
    <option value="111">Item 1</option>
    <option value="112">Item 2</option>
    <option value="113">Item 3</option>
    <option value="114">Item 4</option>
    <option value="115">Item 5</option>
    <option value="116">Item 6</option>
    <option value="117">Item 7</option>
</select>
<select id="block3">     
    <option value="0">Item 0</option>
    <option value="111">Item 1</option>
    <option value="112">Item 2</option>
    <option value="113">Item 3</option>
    <option value="114">Item 4</option>
    <option value="115">Item 5</option>
    <option value="116">Item 6</option>
    <option value="117">Item 7</option>
</select>
<select id="block4">     
    <option value="0">Item 0</option>
    <option value="111">Item 1</option>
    <option value="112">Item 2</option>
    <option value="113">Item 3</option>
    <option value="114">Item 4</option>
    <option value="115">Item 5</option>
    <option value="116">Item 6</option>
    <option value="117">Item 7</option>
</select>
<select id="block5">     
    <option value="0">Item 0</option>
    <option value="111">Item 1</option>
    <option value="112">Item 2</option>
    <option value="113">Item 3</option>
    <option value="114">Item 4</option>
    <option value="115">Item 5</option>
    <option value="116">Item 6</option>
    <option value="117">Item 7</option>
</select>
<button onclick="validate()">validate</button>

JavaScript

validate = function() {
    var bk1 = document.getElementById("block1").value;
    var bk2 = document.getElementById("block2").value;
    var bk3 = document.getElementById("block3").value;
    var bk4 = document.getElementById("block4").value;
    var bk5 = document.getElementById("block5").value;
    
    var test = [bk1, bk2, bk3, bk4, bk5];
    var res = true;
    
    for(var i = 0; i < test.length; i++) {
        if (test[i]>0) {
            if (test.indexOf(test[i], i + 1) >= 0) {
                 res = false; 
                 break;
            } 
        }
    }
    
    if(res){
        alert("no fields the same, safe to move on");
    }else{
        alert("oh no, one of the field are the same");
    }
}