JSFiddle - React, Tailwind, and code Playground
HTML
<h3> Table 1</h3>
<table id="table1" border="1">
<tr>
<td>select any option</td>
<td>
<select>
<option value="--select--">--select--</option>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="vw">VW</option>
<option value="audi" >Audi</option>
</select>
</td>
</tr>
<tr>
<td>select any option</td>
<td>
<select>
<option value="--select--">--select--</option>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="vw">VW</option>
<option value="audi" >Audi</option>
</select>
</td>
</tr>
<tr>
<td>select any option</td>
<td>
<select>
<option value="--select--">--select--</option>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="vw">VW</option>
<option value="audi" >Audi</option>
</select>
</td>
</tr>
</table>
<br>
<h3> Table 2</h3>
<table id="table2" border="1">
<tr>
<td>select any option</td>
<td>
<select>
<option value="--select--">--select--</option>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="vw">VW</option>
<option value="audi" >Audi</option>
</select>
</td>
</tr>
<tr>
<td>select any option</td>
<td>
<select>
<option value="--select--">--select--</option>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="vw">VW</option>
<option value="audi" >Audi</option>
</select>
</td>
</tr>
<tr>
<td>select any option</td>
<td>
<select>
<option value="--select--">--select--</option>
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="vw">VW</option>
<option...
JavaScript
$('#table1 tr').each(function() {
$(this).find('select').change(function(){//alert($(this).val())
if( $('#table1').find('select option[value='+$(this).val()+']:selected').length>1){
alert('option is already selected');
$(this).val($(this).find("option:first").val());
}
});
});
$('#table2 tr').each(function() {
$(this).find('select').change(function(){//alert($(this).val())
if($('#table2').find('select option[value='+$(this).val()+']:selected').length>1){
alert('option is already selected');
$(this).val($(this).find("option:first").val());
}
});
});