simpel elelr hvad??

her koden:
<script language="javascript">
function tjek(form) {
strBox1 = form.box1;
strBox2 = form.box2;
strBox3 = form.box3;
strM = "200"
if (strBox1 + strBox2 + strBox3 > strM) {
strMange = strBox1 + strBox2 + strBox3 - strM
alert("Du har sat " + strMange + " points for meget")
} else if (strBox1 + strBox2 + strBox3 < strM) {
strMange = strM - strBox1 + strBox2 + strBox3
alert("Du har sat " + strMange + " points for lidt")
} else if (strBox1 + strBox2 + strBox3 == strM) {
alert("ok!!")
}
}

</script>
<form onSubmit="return tjek(this)">
<input type="text" name="box2">
<input type="text" name="box2">
<input type="text" name="box3">
<input type="submit" value="tes


men det virker barre ikke??