Cannot read property 'contains' of undefined #1110

Bug Report

Steps to reproduce

When clicking the result switching page in the left search box, an error will be reported

Uncaught TypeError: Cannot read property 'contains' of undefined
at HTMLElement. (docsify.min.js:1)

After query, the source code needs to be modified
Modify 539 lines of source code and add a layer of judgment

What is current behaviour

What is the expected behaviour

Other relevant information

• Bug does still occur when all/other plugins are disabled?

• Your OS:

• Node.js version:

• npm/yarn version:

• Browser version:

• Docsify version:

• Docsify plugins:

Please create a reproducible sandbox

Mention the docsify version in which this bug was not present (if any)