Started working on SitesList component for accepting user input and validation.

assets/js/components/SitesList.react.js

@@ -0,0 +1,28 @@
+var React = require('react');
+
+var SitesList = React.createClass({
+
+    getDefaultProps: function () {
+        return {
+            placeholder: 'http://google.com'
+        };
+    },
+
+    render: function () {
+        return (
+            <div className="form-group">
+                <label htmlFor="sites" className="col-lg-2 control-label">{this.props.label}</label>
+
+                <div className="col-lg-10">
+                    <textarea className="form-control" rows="3" ref="sites"
+                        placeholder={this.props.placeholder}></textarea>
+                    <span className="help-block">{this.props.helpText}
+                        <br/>
+                        One line per site.</span>
+                </div>
+            </div>
+        );
+    }
+});
+
+module.exports = SitesList;

assets/js/events.js

@@ -45,7 +45,7 @@ chrome.tabs.onUpdated.addListener(function (tabId, changeInfo, tab) {
 
     if (changeInfo.status === 'complete') {
         // Get current tab URL.
-        chrome.tabs.query({active: true}, (tabs) => {
+        chrome.tabs.query({active: true}, function(tabs) {
             // If tab updated is the same as active tab
             if (tabId == tabs[0].id) {
                 console.log('recording a heartbeat - tab updated');