Working with html coming from db

I’m tring to build a UI to customize the design and layout of emails.

The flow is: user chooses from a list of predefined email layouts, load the layout style+html in the page, interact with the layout to insert image or text with inline editor triggered by click and handled by ember.js

The problem is to interact with DOM inserted at runtime. so without all the goodness of handlebars helpers and so on. The email DOM is basically a piece of remote data, coming from a db and loaded in ember via ember-data

How do you go about it? Thanks