Since Illustrator is a vectorbased application, it's actually pretty great for designing webpages. Illustrator, like Photohsop, wasn't really developed for webdesign, but that's easily fixed with some configuration and a couple of scripts!
1. Download the scripts by throught the "Download ZIP" button here.
2. Extract the files.
3. Copy the desired plugin folders into the Illustrator application folder's "Presets" > [Your_locale] > "Scripts" subfolder
3. After restarting Illustrator you can find the scripts in the menu "File" > "Scripts";
Note: The Illustrator application folder is usually located in C:/Program Files/Adobe/ on Windows (on osX it's simply located in your Applications folder)
This script let's you generate grids on the active artboard. The script intelligently fills out the blanks for you meaning that you only need to specifiy the known values, e.g. if you know how many columns you want, and the gutter width; you can leave the other fields blank and the script will calculate the optimal column width!
Simple script to rename the current layer, perfect for when you need to clean up your files or send them over to a co-worker.
Repositions the selected object so that it's top left corner is aligned to whole pixels.