How do I pass information from the Content_script to the popup page? (Chrome extensions)

Couple ways to do this, I used the first one in my extension:

1. localStorage. Use sendRequest({}) to pass a message with your variable to the background page, which will then save the variable to localStorage. Once that's done, your popup can access the variable like localStorage["x"]. (It has to go through the background page because at this time, content scripts cannot access localStorage)

2. Plain requests. Pray that the popup is open, and try sending it a message from the content script with the variable in it. Note that this is not a good solution simply because the popup might not be open when you try to send it the variable.

Code Example for #1:

//sendRequests look like this: sendRequest(message - Object, [callback - Function]); //API Docs: //onRequest Listener: http://code.google.com/chrome/extensions/extension.html#event-onRequest //sendRequest Method: http://code.google.com/chrome/extensions/extension.html#method-sendRequest //localStorage: http://www.html5rocks.com/features/storage //From the Content Script //Send request to background.html, no callback chrome.extension.sendRequest({ type: "popup_var", /* In my extensions, because I could often be different types of reqeusts, I use a type variable to identify them */ my_variable: "Sally sold seashells by the seashore" /* Whatever variable you are trying to send */ }); //In background.html chrome.extension.onRequest.addListener( function(request, sender, sendResponse){ if(request.type == "popup_var"){ /* The type of message has been identified as the variable for our popup, let's save it to localStorage */ localStorage["popup_var"] = request.my_variable; } } ); //In popup.html console.log( "Variable from Content Script: "+localStorage["popup_var"] );