Whenever I have encountered heavy HTML generation in javascript, it was almost solely in a stand-alone UI plugin. It makes sense, as it allows to encapsulate the entire plugin in a single .js file (+ a .css to customize styles), thus making it easily reusable, distribuable, and independent from the framework used in the application.

So if you're writing a stand-alone javascript plugin or a generic UI component which you would like to use across different applications, such an approach has its upsides. Otherwise, I think it's both cleaner, easier to write and easier to maintain when you keep html generation away from javascript.

Whenever I have encountered heavy HTML generation in javascript, it was almost solely in a stand-alone UI plugin. It makes sense, as it allows to encapsulate the entire plugin in a single .js file (+ a .css to customize styles), thus making it easily reusable, distribuable, and independent from the framework used in the application.

So if you're writing a stand-alone javascript plugin or a generic UI component which you would like to use across different applications, such an approach has its upsides. Otherwise, I think it's both cleaner, easier to write and easier to maintain when you keep html generation away from javascript and on the server side.