title: change "width" of "linebreaks" of MathJax on Fly
body: <p>As described <a href="http://docs.mathjax.org/en/latest/options/HTML-CSS.html" rel="nofollow noreferrer">here</a>, we can use this to configure  how wide the lines of mathematics can be:</p>
  
  <pre><code>"HTML-CSS": { linebreaks: { automatic: true, width: "30em" } }
  </code></pre>
  
  <p>Is there a way to change the value of the <code>width</code> on fly after that MathJax completed typsetting of formula in the page?</p>