Eclipse has a web browser, but I don't know any straightforward way to open it. I know that if you go to the Eclipse market place and ask for more results it'll open, and if you make the browser open your html you can open it, but is there a more straightforward way to open it? (For example, a button or menu option that says browser?)
Right click a file in left Project Navigator, and in the pop up context menu, chse
Open with ..., and then you can find it in sub menu.
Actually, I don't like to use it.
The Web and Java EE perspective will reveal a button on the toolbar to open a new web browser.
Also, from Window > Show View you find the Internal Web browser view.
The former acts as an editor tab, the later not.
You can add the button and menu option to launch the Internal Web Browser to any perspective. Right click on the toolbar and select "Customize Perspective...". Then click the Command Groups Availability tab and check the Web Browser command group in the list on the left to make it available.