function! ToggleBackground()
    if (g:solarized_style=="dark")
    let g:solarized_style="light"
    colorscheme solarized
else
    let g:solarized_style="dark"
    colorscheme solarized
endif
endfunction
command! Togbg call ToggleBackground()
nnoremap <F5> :call ToggleBackground()<CR>
inoremap <F5> <ESC>:call ToggleBackground()<CR>
vnoremap <F5> <ESC>:call ToggleBackground()<CR>