How can change a styling of javascript alert button?

Question

I want to change a style of javascript alert box.As you can see in many website like
facebook,Here is alert boxex are stlyed.how can I do that.

Answer 1

You can not style alert box, what you could do is create a modal popup

eg.

http://jqueryui.com/dialog/

http://defunkt.io/facebox/

How to code a JavaScript modal popup (to replace Ajax)?

Answer 2

You can't change it; it is implemented by the browser.

Answer 3

You can't style the alert box.

You can create a div put the message in it style it with css and pop it up with javascript.

An example for this can be find in the jQuery UI dialog widget, DEMO