<html>
<head>
<meta charset="utf-8">
<title>DOM API</title>
</head>
<body>
İsim:<input id="isimInput" type="text"/>
Merhaba <span id="isimSpan"></span>!
<script>
var isimInputElement = document.getElementById('isimInput'),
isimSpanElement = document.getElementById('isimSpan');
isimInputElement.addEventListener('keyup', function(){
var isim = isimInputElement.value;
isimSpanElement.innerHTML = isim;
});
</script>
</body>
</html>