Chrome Extension - Open Multiple Tabs

I'm Trying to create a function where I can open Multiple Tabs in Chrome (It's a Extension). I found a function from Google their self, but it won't work with my extension. And I also set tabs as permission in the Manifest.

There's a error appear on the Console everytime:

*Uncaught TypeError: Cannot read property 'create' of undefined at popup.js:29 (anonymous) @ popup.js:29*

Its My Code

for (var i = 0; i < cats.length; i++) {
link = 'http://www.something.com/'+cats[i];
chrome.tabs.create({
    url: link
});