I am working on SharePoint designer to customize page layout in SharePoint 2013
Is there any way to comment and uncomment code like visual studio buttons?
The SharePoint Designer is not considered a dedicated Code editor or IDE like Visual Studio, However, you can add a comment tag through
Note: it's not working with the JS/CSS codes. it's only for HTML code. Also, you will not able comment the highlighted code.
To add a comment on the highlighted HTML, JS, CSS codes, you can create a Code Snippet as mentioned at Comments in SharePoint Designer
For more details, check Comments in SharePoint Designer