Build a Markdown Previewer Test problem

Tell us what’s happening:
I have written the code as per user stories but still the tests don’t execute successfully.

Your code so far
Here is my pen https://codepen.io/sakata_gintoki/pen/moyEOy?editors=0010
Your browser information:

User Agent is: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:65.0) Gecko/20100101 Firefox/65.0.

Link to the challenge:

You have multiple elements with id="editor"

Thank you. Corrected it.