js problem in contact form 7

I have a problem in contact form 7.
My javascript code doesnt work.
Please help me.
Thanks in advance

`<script>
var count = 1;

const selectElement = document.querySelector(‘.selector’);

selectElement.addEventListener(‘change’, (event) => {
prop.innerHTML = “”;
$( “.six-cargo” ).append( “<h3> test </h3> ” );
for (let i = 1; i <= event.target.value; i++)
{

var temp = ‘<div class=”cargo-property”><input type=”text” placeholder=”وزن KG” > <input type=”text” placeholder=”طول CM” ><input type=”text” placeholder=”عرض CM” > <input type=”text” placeholder=”ارتفاع CM” ></div>’;

var a = document.createElement(“div”);
a.innerHTML = temp;

var element = document.getElementById(“prop”);
element.appendChild(a.childNodes[0]);
}

});

</script>