Implement script API:executeScript

chrome/test/data/extensions/api_test/executescript/script3.js

+function getStyle(elem, name) {
+  if (document.defaultView && document.defaultView.getComputedStyle) {
+    name = name.replace(/([A-Z])/g, '-$1');
+    name = name.toLowerCase();
+
+    try {
+      var s = document.defaultView.getComputedStyle(elem, '');
+      return s && s.getPropertyValue(name);
+    } catch (ex) {
+      return null;
+    }
+  } else {
+    return null;
+  }
+}
+
+var bElement = document.getElementById('test2');
+var display = getStyle(bElement, 'display').toLowerCase();
+document.title = display;