The amsCd extensions implements the CD environment for commutative diagrams. See the AMScd guide for more information on how to use the CD environment.

This extension is loaded automatically when the autoload extension is used. To load the amsCd extension explicitly, add '[tex]/amsCd' to the load array of the loader block of your MathJax configuration, and add 'amsCd' to the packages array of the tex block.

window.MathJax = {
  loader: {load: ['[tex]/amsCd']},
  tex: {packages: {'[+]': ['amsCd']}}

Alternatively, use \require{amsCd} in a TeX expression to load it dynamically from within the math on the page, if the require extension is loaded.