从上下文菜单（右键菜单）选择使用您喜欢的编辑器来“查看源代码”、“查看选中部分源代码”或“编辑文本”。
From the context menu (right click), you can "View source" "View selection" or "Edit text" with your favorite editor.
Enabled in (X)HTML, JavaScript, CSS, MathML, SVG, XML, etc.
To use withExEditor, you also need to prepare a host which executes your editor.
Please download the host for withExEditor from asamuzaK/withExEditorHost <https://github.com/asamuzaK/withExEditorHost>.