JSFiddle - React, Tailwind, and code Playground
HTML
<form id="purchase">
<table border="1">
<thead>
<tr>
<th>Menu</th>
<th>Price</th>
<th>Quantity</th>
</tr>
</thead>
<tbody>
<tr>
<td>Coffee</td>
<td id="coffeePrice" value="2.99">$2.99</td>
<td><input type="number"
name="quantityCoffee"
id="quantityCoffee"
value="0"
></td>
</tr>
<tr>
<td>Tea</td>
<td id="teaPrice" value="1.99">$1.99 </td>
<td><input type="number"
name="quantityTea"
id="quantityTea"
value="0"
></td>
</tr>
<tr>
<td>Water</td>
<td id="waterPrice" value="1.25">$1.25</td>
<td><input type="number"
name="quantityWater"
id="quantityWater"
value="0"
></td>
</tr>
</tbody>
</table>
<input type="button"
name="totalCost"
value="Total Cost"
id="checkCost">
<textarea id="display"></textarea>
</form>
JavaScript
document.getElementById("checkCost").onclick = function totalCost(e){
e.preventDefault();
var qC= document.getElementById("quantityCoffee").value;
var qT= document.getElementById("quantityTea").value;
var qW= document.getElementById("quantityWater").value;
var sum= (qC*2.99)+(qT*1.99)+(qW * 1.25);
document.getElementById("display").innerHTML = "Cost is " + sum;
}