InDesign is pretty great for web work, although it doesn't seem that way out of the box.
Here's my preferred setup.
Open Preferences > Units and Increments… and set it up like this.
When you create a new document, set it up like this. You can save these settings as a preset for later.
The scripts DisplayScale.scpt and HexSwatch.jsx are pretty much mandatory for web work.
Open Window > Utilities > Scripts. Right-click on the User folder and choose Reveal in Finder.
Install the scripts DisplayScale.scpt and HexSwatch in this folder.
Run the script DisplayScale and select Scale for screen. Then press cmd + 0 to view your document at 100% – this is how it'll appear in browser.
