I use this code: "alert($('body').width());" to detect the Width of the body-element

and I found out that the body-width is not the same on different Browser,

• On Edge, the Width is: 1535px (vertical Tabs activated)
• On Avast, the Width is: 1583px
• On Firefox, the Width is: 1583px
• On Opera, the Width is: 1545px (vertical Tabs activated)

The width is not the same on Opera and Edge, because on both Browsers are the "vertical Tabs activated", so if I deactivate the vertical Tabs on Edge, I get the same width like Avast or Firefox (1583px).

Would you please help me to detect, if a user has the "vertical Tabs activated" on his Browser and how to get the width of the "vertical Tabs"?