By default, Prism will attempt to highlight all code elements (by calling Prism.highlightAll) on the current page after the page finished loading. This might be a problem if e.g. you wanted to asynchronously load additional languages or plugins yourself.

By setting this value to true, Prism will not automatically highlight all code elements on the page.

You obviously have to change this value before the automatic highlighting started. To do this, you can add an empty Prism object into the global scope before loading the Prism script like this: