It is not possible. This window is displayed by the browser using the platform’s UI kit. It’s not in the DOM, not visible from the CSS or Javascript, there’s nothing you can do. However, some very simple jQuery code can do the trick. How about $(‘a’).confirm(); ?
You’ve just hit a big limitation in JavaScript. Once your code enters the asynchronous world, there is no way to get back to a classic procedural execution flow. In your example, the solution would be to make a loop waiting for the response to be filled. The problem is that JavaScript does not provide any … Read more
In short, you can’t. You might want to consider looking into using something like a jQuery UI dialog instead.
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/
A simple inline JavaScript confirm would suffice: <form onsubmit=”return confirm(‘Do you really want to submit the form?’);”> No need for an external function unless you are doing validation, which you can do something like this: <script> function validate(form) { // validation code here … if(!valid) { alert(‘Please correct the errors in the form!’); return false; … Read more
Update (2017) Modern browsers now consider displaying a custom message to be a security hazard and it has therefore been removed from all of them. Browsers now only display generic messages. Since we no longer have to worry about setting the message, it is as simple as: // Enable navigation prompt window.onbeforeunload = function() { … Read more