JSFiddle - React, Tailwind, and code Playground

HTML

<form name="bibi">
<table border=1 id="tab">
<tr>
	<td>Produits</td><td>Quantité</td><td>Prix Unitaire</td><td>Total</td>
</tr>
<tr>
    <td>ACIDAC 300MG B/14 CP</td><td>2</td><td>83050</td><td><input type='text' value='166100' /></td>
</tr>
<tr>
    <td>Artequin 600/750 AD CP</td><td>3</td><td>78400</td><td><input type='text' value='235200' /></td>
</tr>
</table>
</form>
<h4 style="float:right;">Montant total :<input type="text" id="montanttotal" onClick="calculTotal();" /></h4>

JavaScript

function calculTotal(){
	var all_input = document.getElementById("tab").getElementsByTagName("input");
    var total = 0;
	for (i=0;i<all_input.length;i++){
		total = total + parseFloat(all_input[i].value); 
	}
    document.getElementById("montanttotal").value = total;
}