Extension that Injects scripts into pages on Google Chrome

content-script.js

'use strict';

var s = document.createElement('script');
s.src = chrome.extension.getURL('injection.js');
s.onload = function() {
    this.parentNode.removeChild(this);
};
(document.head || document.documentElement).appendChild(s);

injection.js

'use strict';

// Do something like modifying pages.

manifest.json

{
    "name": "Injector",
    "manifest_version": 2,
    "version": "0.0.1",
    "description": "Inject custom script into pages.",
    "permissions": ["tabs", "http://*/*"],
    "content_scripts" : [{
        "matches" : ["https://pagetoinject.com/*"],
        "js" : ["content-script.js"]
    }],
    "web_accessible_resources": ["injection.js"]
}