The Google Chrome Web Store has a nice library of extensions to use for web designers and developers. Here’s a few that may interest you and are they are free to install.
- PerfectPixel by WellDoneCode – Allows you to match your design to your website with an overlay, so you can get the perfect end results.
- – Provides a rich visual representation for HTML elements, DOM elements, and Box Model shading.
- Resolution Test – Allows you to test web pages in different screen resolutions and even custom resolutions.
- Web Developer – Adds a toolbar with an nice set of developer tools, such as reviewing CSS, forms, images, resizing browser, check accessibility information, outlines, color picker, display ruler, validations and more.