Krot,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<input type="text" name="name" placeholder="Имя"/>
<script>
var input = document.getElementsByTagName('input');
for (var i = 0; i < input.length; i++){
var pla = input[i].placeholder
input[i].value = pla;
input[i].onfocus = function() {
this.value = '';
}
input[i].onblur = function() {
this.value = this.value ? this.value:pla;
};
};
</script>
</body>
</html>