I do not think you can change the confirm dialog box button dialog, but you can make your own confirmation box:
Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>New document</title>
<style type="text/css">
div#fake_box{
position: absolute;
top: 100px;
left: 200px;
height: 88px;
width: 200px;
border: solid black 2px;
background-color: gray;
color: black;
text-align:center;
display:none;
}
</style>
<script type="text/javascript">
function show_box()
{
document.getElementById("fake_box").style.display = "block";
}
</script>
</head>
<body>
<button onclick="show_box()">A question</button>
<div id="fake_box">
<br>What are you wearing<br><br>
<button style="float:left;">Yes</button>
<button style="float:right;">No</button>
</div>
</body>
</html>