Modern browsers usually have the option to change the default display font for web pages that do not have their font defined in the layout/css. Chrome for example: https://support.google.com/chrome/answer/95416?hl=en , http://i40.tinypic.com/swsnz5.jpg.
As far as I know, the current and Java 8 version of JavaFX do not have the option to do this. Also the default font sometimes looks blurry: http://i.stack.imgur.com/X6Jow.png (left = chrome, right = SimpleSwingBrowser). It seems that it is always using the "System Regular" font defined in javafx.scene.text.Font.java