WYSIWYG Editor for Mathematical Equations using MathJax

Question

I am trying to build WYSIWYG Editor to write Mathematical Formulas using MathJax. I am trying to select random content from the textarea and pasting it into

Answer 1

Problem Solved

just insert

    MathJax.Hub.Queue(["Typeset", MathJax.Hub, "pasteselectedContent"]);

after line 32

pasteselectedContent.textContent = selectedContent.value.substring(0,start) + " " + replace + " " + selectedContent.value.substring(end,textlength);