Show the developer tools on Safari so u can use safari to check how the page looks like in other browsers. It may not be 100% fool proof but better than nothing.

You can set it under Perference > Advance > and check "Show Develop menu in menu bar". After that close the window and you will see the word "Developer" on the top Menu and see the different drop down option.

From Catrina of Pixelatwork.com