g:search()

function! g:search()
  let search_str = ''
  let tmp = &l:hlsearch
  try
    setlocal hlsearch
    while 1
      let n = getchar()
      if n == char2nr("\<cr>")
        break
      elseif n == char2nr("\<esc>")
        break
      elseif n == char2nr("\<C-h>") || n == char2nr("\<bs>") || char2nr(n) == 0x80
        if 0 < len(search_str)
          let search_str = search_str[:-2]
        else
          break
        endif
      else
        let search_str .= nr2char(n)
      endif
      silent! execute '/' . search_str
      redraw
      echo '/' . search_str
    endwhile
  finally
    let &l:hlsearch = tmp
  endtry
endfunction
nnoremap <silent>   /     :<C-u>call g:search()<cr>