Fail to see math symbol in preview

[yushangakki]

Problem summary: fail to see math symbol in preview

Expected: To see math symbols, like I type $\dfrac{1}{2}$

Environment Information

• OS: Macos 10.14.4
• Vim / Neovim version:VIM - Vi IMproved 8.1 (2018 May 18, compiled Jul 21 2019 22:54:00)
  macOS version
  Included patches: 1-1722
  Compiled by Homebrew
• Browser: Chrome Version 76.0.3809.100 (Official Build) (64-bit)

Provide the debug output (required)

Run cat my_markdown_file.md | instant-markdown-d --mathjax --debug and paste the
console output here:

(node:98365) [DEP0066] DeprecationWarning: OutgoingMessage.prototype._headers is deprecated
connection established!

Steps to reproduce the issue (required)

Start with command you used to install instant-markdown-d

1.sudo npm -g install instant-markdown-d
2.instant-markdown-d --mathjax
3.

Screen shot (if possible)

[ashwinvis]

Can you generate a log file:

let g:instant_markdown_logfile = '/tmp/instant_markdown.log'

[ashwinvis]

It muse be because the old version of instant-markdown-d was used.