I’m working on a web application where I have Google Docs viewer embedded in an iframe to display Word documents. Users can view and edit these documents within the iframe.
The problem I’m facing is that I need to capture text that users select inside the Google Docs iframe and automatically populate it into an input field that exists outside the iframe on my main webpage.
Additionally, I would like to modify the background color of the text selection to make it more visible to users.
Is there a way to achieve this cross-iframe communication? Any JavaScript solutions or APIs that might help with this functionality?
Unfortunately, you’re hitting a wall here because of browser security policies. Google Docs viewer has strict cross-origin restrictions - you can’t access selection events or modify styling from your parent frame. I’ve been down this road before and had to completely change my approach. Here’s what actually works: build a custom document viewer with PDF.js for PDFs, or convert your docs to HTML so you have full control. You could also try the Google Drive API with proper auth, but users need to grant permissions first. The iframe sandbox isolates Google Docs viewer from your app by design - it’s a security feature, not a bug. Most devs I know just redesign their workflow instead of fighting these constraints.
Hit this same problem six months back building a document review system. Google Docs viewer’s cross-origin restrictions are a nightmare - you can’t intercept text selections or change styling via JavaScript from your parent page. I switched to Microsoft Office Online viewer instead. It’s got better API support, though still pretty limited. Also tried using Google Apps Script to build a custom web app that handles document display and selection events, then talks back to your main app through URL parameters or a REST endpoint. More work, but you get the control you actually need. Changing background colors is especially brutal since Google locks down their viewer’s DOM structure completely.
totally get ur frustration - that google docs iframe is tricky. postMessage() works for some stuff, but not for what u need. maybe check out other ways to handle doc viewing, it could save u some hassle.