JSFiddle - React, Tailwind, and code Playground

HTML

<form  action="stocksubmit.php" method="post" name="frm" id="frm"> 
<table width="40%" border="2" cellpadding="0" cellspacing="0" id="table1">   <tr>
<td><strong>ITEMS</strong></td>
<td><strong>STOCK</strong> </td>
<td><strong>UNIT RATE</strong> </td>
<td><strong>PER ITEM</strong> </td>   </tr>  <tr>
<td><input name="items_0" type="text" id="items_0" size="20" class="item" maxlength="20" /></td>
<td><input name="stock_0" type="text" id="stock_0" size="20" class="stock" maxlength="20" /></td>
<td><input name="unit_rate_0" type="text" id="unit_rate_0"  class="unit_rate" size="20"  maxlength="12" /></td>
<td><input name="per_item_0" type="text" id="per_item_0" class="per_item" size="20" maxlength="12" /></td>

</tr>

</table> <input id="addbutt" type="button" value="Add" /> <input name="submit"   type="submit" value="submit" /> <label> <input name="h" type="hidden" id="h" value="0" /> </label>  
</form>

JavaScript

var test_asd = 0;

$('#addbutt').click(function() {
    $(":text").each(function(){
        test_asd += parseInt($(this).val());
    });
    alert(test_asd);
});