In an attempt to solve a similar situation I've come across this example and adapted it. It uses JQUERY UI Dialog as Nikhil D suggested. Here is a look at the code:

HTML:

<link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.6/themes/smoothness/jquery-ui.css" rel="stylesheet"/>
<input type="button" id="box" value="Confirm the thing?" />
<div id="dialog-confirm"></div>

JavaScript:

$('#box').click(function buttonAction() {
  $("#dialog-confirm").html("Do you want to do the thing?");

  // Define the Dialog and its properties.
  $("#dialog-confirm").dialog({
    resizable: false,
    modal: true,
    title: "Do the thing?",
    height: 250,
    width: 400,
    buttons: {
      "Yes": function() {
        $(this).dialog('close');
        alert("Yes, do the thing");
      },
      "No": function() {
        $(this).dialog('close');
        alert("Nope, don't do the thing");
      }
    }
  });
});

$('#box').click(buttonAction);

I have a few more tweaks I need to do to make this example work for my application. Will update this if I see it fit into the answer. Hope this helps someone.

Create your own confirm box:

Copy<div id="confirmBox">
    <div class="message"></div>
    <span class="yes">Yes</span>
    <span class="no">No</span>
</div>

Create your own confirm() method:

Copyfunction doConfirm(msg, yesFn, noFn)
{
    var confirmBox = $("#confirmBox");
    confirmBox.find(".message").text(msg);
    confirmBox.find(".yes,.no").unbind().click(function()
    {
        confirmBox.hide();
    });
    confirmBox.find(".yes").click(yesFn);
    confirmBox.find(".no").click(noFn);
    confirmBox.show();
}

Call it by your code:

CopydoConfirm("Are you sure?", function yes()
{
    form.submit();
}, function no()
{
    // do nothing
});

You'll need to add CSS to style and position your confirm box appropriately.

Working demo: jsfiddle.net/Xtreu

Unfortunately, there is no cross-browser support for opening a confirmation dialog that is not the default OK/Cancel pair. The solution you provided uses VBScript, which is only available in IE.

I would suggest using a Javascript library that can build a DOM-based dialog instead. Try Jquery UI: http://jqueryui.com/

You’re probably looking for confirm(), which displays a prompt and returns true or false based on what the user decided:

if (confirm('Are you sure you want to save this thing into the database?')) {
  // Save it!
  console.log('Thing was saved to the database.');
} else {
  // Do nothing!
  console.log('Thing was not saved to the database.');
}

I don't believe so. In JS, confirm() is specified to only use the OK and Cancel buttons.

If you want something more complicated, you'll have to make your own dialog, or use a third-party one that provides your desired functionality (yes, including jQuery, unfortunately).

The javascript confirm dialog cannot be customized.

If you require dialog customization I would suggest looking at JQuery UI - Dialog