tell application "Safari"
  set screen_width to (do JavaScript "screen.availWidth" in document 1)
  set screen_height to (do JavaScript "screen.availHeight" in document 1)
end tell
 
tell application "System Events"
  set myFrontMost to name of first item of (processes whose frontmost is true)
end tell
 
tell application "Finder"
  set {desktopTop, desktopLeft, desktopRight, desktopBottom} to bounds of desktop
end tell
 
try
  tell application "System Events"
    tell process myFrontMost
      set {{w, h}} to size of drawer of window 1
    end tell
  end tell
on error
  set {w, h} to {0, 0}
end try
 
tell application "System Events"
  tell process myFrontMost
    try
      set {{w, h}} to size of drawer of window 1
    on error
      set {w, h} to {0, 0}
    end try
    set position of window 1 to {0, 0}
    set size of window 1 to {screen_width - w, screen_height}
  end tell
end tell