JSFiddle - React, Tailwind, and code Playground

HTML

<table id='tblselect' class=normal2 style='font-size:0.6em;'>
<tr><th align='right'>Shipment Type: </th>
<td><select name='shiptype' id="shiptype" onchange="">
        <option value="0"> Please select... </option>
        <option value="1"> LOCAL </option>
        <option value="2"> IMPORT </option>
      </select></td></tr>
</table>    
<br>



<table id="t1" class=normal2 style='font-size:0.6em;'>

<tr><th align='right'>Shipment Type:</th>
<td><b><input type='text' name='ship' value='LOCAL' readonly /></b></td></tr>

<tr><th align='right'>Reference Number: </th>
<td><b><input type='text' name='ref_no' value="<?php echo $localrefnumb ?>" readonly /></b></td></tr>

<tr><th align='right'>Supplier: </th>
<td><select name='supplier'>
    <option value='&nbsp;'> Please select... </option>
    <option value='Supplier 1'> Supplier 1 </option>
    <option value='Supplier 2'> Supplier 2 </option>
    <option value='Supplier 3'> Supplier 3 </option>
      </select></td></tr>

<tr><th align='right'>Description: </th>
<td><input type='text' name='description' size='70' /></td></tr>

<tr><th align='right'>PO No: </th>
<td><input type='date' name='po_no' /></td></tr>

<tr><th align='right'>Invoice Number: </th>
<td><input type='text' name='inv_number' /></td></tr>

<tr><th align='right'>Receive Qty: </th>
<td><input type='text' name='r_qty'/></td></tr>

<tr><th align='right'>No. of Boxes/Packs: </th>
<td><input type='text' name='no_boxes'/></td>

<tr><th align='right'> </th>
<td></td></tr>

<tr><th align='right'> </th>
<td align='left'><input type='submit' name='local_btn' value='SAVE' style='font-size:2em;'> &nbsp;&nbsp;&nbsp;&nbsp; <input type='submit' name='local_cancel' value='CANCEL' style='font-size:2em;'></td></tr>
</table>



<table id="t2" class=normal2 style='font-size:0.6em;'>

<tr><th align='right'>Shipment Type:</th>
<td><b><input type='text' name='ship2' value='IMPORT' readonly /></b></td></tr>

<tr><th align='right'>Reference Number: </th>
<td><b><input...

JavaScript

$('#shiptype').change(function () {
   $('#t1,#t2').hide();
      var tableValue = $(this).val();

    if (tableValue == 1) {
        $('#t1').show();
    } else if (tableValue == 2) {
        $('#t2').show();
    }   

}); 

$('#t1,#t2').hide();