Expression Web Preview in Browser
Before you can preview your work in browsers other than the default installed on your computer, you must edit the browser list.
File | Preview in Browser | Edit Browser List
Add whichever browsers you have installed on your system and select the resolutions you want. Click OK.
If you use the F12 key to Preview your page, it will open the last browser used. If you want to preview the page in other or multiple browsers File | Preview in Browser and make your choices from the list.
