メモ 

<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>無題ドキュメント</title>
<script type="text/javascript">
window.onload = function() {
  document.calcForm.btnA.onclick = aaa;
}

function aaa(){
	alert("A");
}

</script>
</head>

<body>
<form name="calcForm">
<div><input type="button" value="ボタンA" name="btnA"></div>
<div><input type="button" value="ボタンB" name="btnB" onClick="aaa();"></div>
</form>
</body>
</html>