Vim Syntastic Cannot show any error in JSHint - html

Question

I just start using Vim. I have Syntastic installed. But Syntastic cannot show any error.
For instance, I use Syntastic to edit HTML and use JSHint to check for error:
When I type SyntasticInfo, the following shows up:
Syntastic info for filetype: html
Available checker(s): jshint
Currently Available checker(s): jshint
But still no error comes up.
The main point is: I understand that there should be a gutter on the left side of the vim after installing Syntastic. And this does not show up. Why the gutter not show up?
Here is my vimrc
set nocompatible
source $VIMRUNTIME/vimrc_example.vim
source $VIMRUNTIME/mswin.vim
behave mswin
set diffexpr=MyDiff()
function MyDiff()
let opt = '-a --binary '
if &diffopt =~ 'icase' | let opt = opt . '-i ' | endif
if &diffopt =~ 'iwhite' | let opt = opt . '-b ' | endif
let arg1 = v:fname_in
if arg1 =~ ' ' | let arg1 = '"' . arg1 . '"' | endif
let arg2 = v:fname_new
if arg2 =~ ' ' | let arg2 = '"' . arg2 . '"' | endif
let arg3 = v:fname_out
if arg3 =~ ' ' | let arg3 = '"' . arg3 . '"' | endif
let eq = ''
if $VIMRUNTIME =~ ' '
if &sh =~ '\<cmd'
let cmd = '""' . $VIMRUNTIME . '\diff"'
let eq = '"'
else
let cmd = substitute($VIMRUNTIME, ' ', '" ', '') . '\diff"'
endif
else
let cmd = $VIMRUNTIME . '\diff'
endif
silent execute '!' . cmd . ' ' . opt . arg1 . ' ' . arg2 . ' > ' . arg3 . eq
endfunction
call pathogen#runtime_append_all_bundles()
call pathogen#helptags()
set lines=50 columns=200
colorscheme darkblue
filetype plugin on
set omnifunc=syntaxcomplete#Complete
let g:syntastic_check_on_open=1
let g:syntastic_enable_signs=1
let g:syntastic_javascript_checkers = ['jslint']
let g:syntastic_html_checkers = ['tidy']
let g:gitgutter_sign_column_always=1
After some thought, I now tried to use htmltidy. I install htmltidy by:
npm install htmltidy -g
But still no result. Thank you for your help!