JSFiddle - React, Tailwind, and code Playground

HTML

value1:<input type="text" id="total_1" ><br>
value2:<input type="text" id="total_2" ><br>
value3:<input type="text" id="total_3" ><br>
value4:<input type="text" id="total_4" ><br>
value5:<input type="text" id="total_5" ><br>
total:<input type="text" id="totalresult" >
<button type="button" onclick="getTotal(); return false;">Get total</button>

JavaScript

function getTotal() {
                var sum = 0;
        for (i = 1; i <=5 ; i++) {
        var total = document.getElementById('total_' + i.toString()).value;
    if(isNaN(total) || total.indexOf(' ') == 1) {
        alert("Please type a number");
        document.getElementById("totalresult").value = "I cant sum alphanumerics";
        return false;
    } 

    if (total != '') {
        sum = parseFloat(total) + sum;
        document.getElementById('totalresult').value = sum;
    }
}
}