user_i,
Вариант ...
<!DOCTYPE html>
<html >
<head>
<title></title>
</head>
<body>
<input type="button" name="go" value="go" id="button" />
<script type="text/javascript">
function doSomething(a) {
return function ()
{
alert(a)
}
}
document.getElementById('button').onclick = doSomething('Спасибо')
</script>
</body>
</html>