Notes

<script src="//ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
<script>
function kontrol() {
var us = document.getElementById("uname").value;
var pass = document.getElementById("psw").value;

if (us == "admin" && pass == "admin") {
alert('doğru');
window.open("go:anasayfa");
} else {
alert('yanlıs');
}

} </script>
<form action="" method="post">
<div class="imgcontainer">
<img src="img_avatar2.png" alt="Avatar" class="avatar">
</div>
<div class="check">
</div>
<div class="container">
<label for="uname"><b>Kullanıcı Adı</b></label>
<input type="text" placeholder="Kullanıcı Adı Giriniz" name="uname" required>

<label for="psw"><b>Şifre</b></label>
<input type="password" placeholder="Şifre Giriniz" name="psw" required>

<button onclick="kontrol">Giriş Yap</button>
<button type="button" class="cancelbtn">Şifre Al</button>
<label>
<input type="checkbox" checked="checked" name="remember">Beni Hatırla
</label>
</div>



</form>

<style>
/* Bordered form */
form {
border: 3px solid #f1f1f1;
}

/* Full-width inputs */
input[type=text], input[type=password] {
width: 100%;
padding: 12px 20px;
margin: 8px 0;
display: inline-block;
border: 1px solid #ccc;
box-sizing: border-box;
}

/* Set a style for all buttons */
button {
background-color: #4CAF50;
color: white;
padding: 14px 20px;
margin: 8px 0;
border: none;
cursor: pointer;
width: 100%;
}

/* Add a hover effect for buttons */
button:hover {
opacity: 0.8;
}

/* Extra style for the cancel button (red) */
.cancelbtn {
width: 100%;
padding: 14px 18;
background-color: #f44336;
}

/* Center the avatar image inside this container */
.imgcontainer {
text-align: center;
margin: 24px 0 12px 0;
}

/* Avatar image */
img.avatar {
width: 40%;
border-radius: 50%;
}

/* Add padding to containers */
.container {
padding: 16px;
}

/* The "Forgot password" text */
span.psw {
float: right;
padding-top: 16px;
}

/* Change styles for span and cancel button on extra small screens */
@media screen and (max-width: 300px) {
span.psw {
display: block;
float: none;
}
.cancelbtn {
width: 100%;
}
}
</style>
</script>

</script>