CODEWITHSUNDEEP
javascript
swydell
swydell

Reputation: 2022

Homework Sales calculator

Yesterday I submitted this problem, got terrific responses but my code still didn't work. I modified my code based on another student's code that works, but my code still won't calculate but it validates in javascript. Any suggestions. This homework is due TONIGHT! 

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4       /loose.dtd">
<html>
<head>
<title>Price Calculator</title>
<script type="text/javascript">
    function fixOrder() {
        const TAX = 0.975;
        var numPrice;
        var total;
        var tax;

        numPrice = parseFloat(document.getElementById("cost").value, 10);
        tax      = parseFloat(document.getElementById("tax").value, 10);
        total    = parseFloat(document.getElementById("total").value, 10);
        numPrice = numPrice * TAX;
        total    = numPrice;
        total    = document.getElementById("total").value = "$" + total.toFixed(2);

        if (isNaN(numPrice)) {
            alert("Sorry,you must enter a numeric value to place order");
            numPrice = 0;
        }
    }
</script>

</head>

<body bgcolor="#00f3F1">

    <h1 align="left">Price Calculator</h1>

    <form name="form" id="form">
       <p>Price: <input type="text" id="cost" name="cost" value="" onchange=
       "fixOrder" /></p>

       <p>Tax: &nbsp; <input type="text" id="tax" name="tax" value="" onchange=
       "fixOrder" /></p>

       <p>Total: <input type="text" id="total" name="total" value="" disabled=
       "disabled" /></p>
    </form>
</body>
</html>

Upvotes: 3

Views: 2726

Answers (3)

Jason Gennaro
Jason Gennaro

Reputation: 34855

You need to change the onchange to 

fixOrder()

Upvotes: 2

vol7ron
vol7ron

Reputation: 42109

JS Fiddle

Your onchange event is onchange="fixOrder" which is not really doing anything. If you change it to fixOrder() you will call the function fixOrder when the change event is fired.

Furthermore:

  • I don't think const is a reserved word in JavaScript. I don't think JS has constants. You should change that line from const TAX to var TAX;
  • Unlike parseInt, which takes two arguments (string and base/radix), parseFloat only takes one argument (string), so you can remove the , 10 from it

I imagine you want something like:

function fixOrder() {
    var TAX = 0.0975;
    var numPrice;
    var total;
    var tax;

    numPrice = parseFloat(document.getElementById("cost").value);
    tax      = parseFloat(document.getElementById("tax").value);
    total    = parseFloat(document.getElementById("total").value);

    numPrice = numPrice + (tax || numPrice * TAX);
    total    = numPrice;
    var dec  = new Number((total+'').split('.')[1])  || 0;
    total    = document.getElementById("total").value =
                  "$" + Number(parseInt(total)
                      + '.'
                      + Math.round(
                          ( (dec+''.split('').reverse().join('') )/100 + '').split('').reverse().join('')
                        )).toFixed(2);
                        );

    if (isNaN(numPrice)) {
        alert("Sorry,you must enter a numeric value to place order");
        numPrice = 0;
    }
}

This will use the dollar amount of tax you enter, or if that doesn't exist, it will use the constant rate that you have supplied at the beginning (this was changed from .975 to .0975).

Also, notice the new calculation from total, we're taking the decimal part of the number, dividing it by 100 to get to two decimal places, reversing it back so it's in the proper order again, and then rounding it to the nearest 1 (cent).

HTML Body:

  <h1 align="left">Price Calculator</h1>

  <form name="form" id="form">
     <p>Price: <input type="text" id="cost" name="cost" value="" onchange="fixOrder()" /></p>

     <p>Tax: &nbsp; <input type="text" id="tax" name="tax" value="" onchange="fixOrder()" /></p>

     <p>Total: <input type="text" id="total" name="total" value="" disabled="disabled" /></p>
  </form>

Upvotes: 2

Bart1990
Bart1990

Reputation: 255

When calling a function in JavasScript by an event, you need to mention the () after the name of the function you want to call.

Upvotes: 0

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