Make plural when quantity is greater than 1

i already have this code but it does not work as expected.

the word "piece" should be changed to "pieces" when the quantity is greater than 1.

<span class="counter b">2 <span id="unitpcs"></span></span>

<script type="text/javascript">

var q = document.getElementsByTagName("span");
var a = myFunction(q.innerHTML);
document.getElementById("unitpcs").innerHTML = x;

function myFunction() {
if (a > 1) {
        x = "pieces";
    } else {
        x = "piece";
    }
}
</script>

Currently, when the quantity is equal to one (1), the result is correct: 1 piece.

If the quantity becomes two (2), the result is not correct: 2 piece The correct output should be "2 pieces".

Any solution is highly appreciated. Thanks in advance!

1. You forgot to specify a as the parameter of myFunction().
2. You overlooked that q is an array of two span elements.
3. You neglected to convert the .innerHTML to a number.

<span class="counter b">2 <span id="unitpcs"></span></span>

<script type="text/javascript">
var q = document.getElementsByTagName("span");
myFunction(parseFloat(q[0].innerHTML)); // first span, convert to number
document.getElementById("unitpcs").innerHTML = x;

function myFunction(a) {
if (a > 1) {
        x = "items";
    } else {
        x = "item";
    }
}
</script>