<div align="center">
<html>
<head>
<title></title>
<style>
input{
font-size: 20px;
}
#ort{
color: red;
font-size: 30px;
}
#sonuc{
color: red;
font-size: 30px;
}
</style>
</head>
<body>
<form name="ortalama">
9.Sınıf<br />
<input style="border-radius:6px; border-color:white;" name="txt9sinif" type="text" placeholder="ör.82.50 | max.100"/><br /><br />
10.Sınıf<br />
<input style="border-radius:6px;" name="txt10sinif" type="text" placeholder="ör.82.50 | max.100"/><br /><br />
11.Sınıf<br />
<input style="border-radius:6px;" name="txt11sinif" type="text" placeholder="ör.82.50 | max.100"/><br /><br />
12.Sınıf<br />
<input style="border-radius:6px; opacity:4px;" name="txt12sinif" type="text" placeholder="ör.82.50 | max.100"/><br /><br />
<input style="color:white; background-color: black; border-radius: 6px; height: 50px; width: 180px;" id="hesap" onclick="hesapla()" type="button" value="HESAPLA" />
</form>
<div id="ort">
</div>
<br/>
<br/>
<br/>
<div id="sonuc">
</div>
<script>
function hesapla(){
var a1=document.ortalama.txt9sinif.value;
var a2=document.ortalama.txt10sinif.value;
var b1=document.ortalama.txt11sinif.value;
var b2=document.ortalama.txt12sinif.value;
var ortalama=(Number(a1)+Number(a2)+Number(b1)+Number(b2))/4;
var durum="";
document.getElementById("ort").innerHTML=ortalama;
document.getElementById("sonuc").innerHTML=durum;
}
</script>
</body>
</html>
</div>