.tofix(2) Returning more than 2 numbers after decimals

Question

I have the following code:

Type a value in the Centimeter field to convert the value to Feet:

<p>
<label>Centimeter</label>
<input id="inputCentimeter" type="number" placeholder="Centimeter" 
oninput="LengthConverter(this.value)" 
onchange="LengthConverter(this.value)">
</p>
<p>Feet: <span id="outputFeet"></span></p>

<script>
function LengthConverter(valNum) { document.getElementById("outputFeet").innerHTML=valNum*0.0328084.toFixed(2);
}
</script>

On most inputs, the returns output has the right format, but on some given sizes (for example 155cm) it returns several decimals:

155 Cm=4.6499999999999995 Ft

Answer 1

Wrap the prior operation with (). It first evaluates the function call on the number, so first goes 0.0328084.toFixed(2) then the result of this with valNum.

(valNum*0.0328084).toFixed(2)

Example

function LengthConverter(valNum) {
   document.getElementById("outputFeet").innerHTML = (valNum*0.0328084).toFixed(2);
}

<p>
<label>Centimeter</label>
<input id="inputCentimeter" type="number" placeholder="Centimeter" 
oninput="LengthConverter(this.value)" 
onchange="LengthConverter(this.value)">
</p>
<p>Feet: <span id="outputFeet"></span></p>

Answer 2

Just calculate the value first and then do the rounding up. To calculate the value first, put them inside the parentheses.

(valNum*0.0328084).toFixed(2)

Your code is modified below.

<p>
<label>Centimeter</label>
<input id="inputCentimeter" type="number" placeholder="Centimeter" 
oninput="LengthConverter(this.value)" 
onchange="LengthConverter(this.value)">
</p>
<p>Feet: <span id="outputFeet"></span></p>

<script>
function LengthConverter(valNum) { document.getElementById("outputFeet").innerHTML=(valNum*0.0328084).toFixed(2);
}
</script>