Coda is simply one of the best-made applications for OS X and is truly a top-notch web development environment.
One of the frustrating things about it though is that, by default, you can’t see exactly what the code you enter will actually appear like in a user’s browser. However, with Coda’s Split feature, you can actually have the screen split into two: one for code and one for previewing. (Technically you can have more than two splits.)
To split a coding window into two, press the icon at the far right of the tab bar while in Edit mode. (It is a “+” sign with three horizontal lines adjacent.) Then, click in whichever split you want to be used for previewing. Then, enter Preview mode by selecting “Preview” from the top bar of the application. Now, one split should switch to preview mode while the other stays in a coding view.
