Javascript: detecting if checkbox checked not working

javascript checkbox onclick

26,651

Solution 1

the issue is that you're document.orderform is your form and getElementById is on document.

You can either do:

document.getElementById(x).checked

or:

document.orderform.elements[x].checked

Solution 2

Can you try to put this condition

if (document.getElementById('discountbox').checked == true)

Solution 3

Try something a bit simpler:

if (document.getElementById(x).checked)

26,651

Author by

NQQ

Updated on April 06, 2020

Comments

NQQ about 4 years

I've dug through all the tutorials and have been pulling my hair out trying to get this to work.

The onClick fires properly, but it never makes it inside the IF loop where it checks if the checkbox has been checked.

<!DOCTYPE html>
<html>
<head>
</head>

<header>
<script>

function updateTotal() {
document.orderform.total.value = 1*document.orderform.subtotal.value + 1*document.orderform.tax.value + 1*document.orderform.shipping.value;
}

**function applyDiscount(x) {


if (document.orderform.getElementById(x).checked == true) {
alert("Made it in if");
document.orderform.subtotal.value = .7*document.orderform.subtotal.value;
updateTotal();
}**

}

</script>
</header>

<body>


<section>
<h1>H1 here</h1>

<article>
<p>Article text here</p>
</article>

<form name="orderform" id="orderform" method="post" action="result.php">

<label for="firstname">First Name</label>
<input type="text" name="firstname" id="firstname" placeholder="Enter First Name Here" />
<br />


<label for="subtotal">Subtotal</label>
<input type="text" name="subtotal" id="subtotal" value="10" onChange="updateTotal()"/>
<br />

<label for="shipping">Shipping</label>
<input type="text" name="shipping" id="shipping" value="2" onChange="updateTotal()"/>
<br />

<label for="tax">Tax</label>
<input type="text" name="tax" id="tax" value="1" onChange="updateTotal()" />
<br />

<label for="total">Total</label>
<input type="text" name="total" id="total" value="13" />
<br />

<label for="discountbox">Apply 30% discount</label>
<input type="checkbox" name="discountbox" id="discountbox" onClick="applyDiscount(this.id)"/>

<input type="submit" name="submit" />

</form>

</section>

<footer>
<p>Footer here</p>
</footer>


</body>