Javascript onchange

Hello,

Is it possible to use javascript in contact form7

I am trying to use this code,

Totale investering in het project:
[number* totale_investering id:totalcost]
Financieringsbedrag ( maximaal 75% van totale financi?le investering):
[number* financieringsbedrag onchange="test()" id:financeamount]
<p id="bedrag"></p>

<script>
function test(){
var financeamount  = document.getElementById("financeamount").value;
var totale_investering  = document.getElementById("totale_investering").value;

if (financeamount <= totale_investering/ 100 * 75 ){
         document.getElementById("bedrag").innerHTML = " ";
    }
else
{
 document.getElementById("bedrag").innerHTML = "Financieringsbedrag ( maximaal 75% van totale financi?le investering):";
}
}

</script>

I hope someone can help me with this .
thank you in advance

timhartog