JSFiddle - React, Tailwind, and code Playground

HTML

<select name="top5" size="3" id="dropdown">
    <option>Some Value</option>
</select>

<input type="text" id="num" value="2"/> 
<input type="button" id="btn" value="Add"/>
<table id="tblspecializations">
    <tr>
        <td>Some Value</td>
        <td>2</td>
        <td>IGNORE ME</td>
    </tr>
</table>

JavaScript

$(function(){
        $("#btn").click(function(){
            var table = $("#tblspecializations");
            var firstTd = $("td:first", table);
            var secondTd = firstTd.next();
            
            if(firstTd.text() == $("#dropdown").val() && secondTd.text() == $("#num").val())
                alert("Error: You're trying to add the same entry");
        });
    });