How to determine the Opera browser using JavaScript

Now that Opera uses the Chrome rendering engine, the accepted solution no longer works.

The User Agent string shows up like this:

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1500.52 Safari/537.36 OPR/15.0.1147.132

The only identifier for Opera is the OPR part.

Here's the code I use, which should match the old Opera or the new Opera. It makes the Opera var a boolean value (true or false):

var Opera = (navigator.userAgent.match(/Opera|OPR\//) ? true : false);

The above answers no longer work in the new Opera 30. Since Opera now use Chromium. Please use the below:

var isChromium = window.chrome,
    isOpera = window.navigator.userAgent.indexOf("OPR") > -1 || window.navigator.userAgent.indexOf("Opera") > -1;
if(isChromium !== null && isOpera == true) {
   // is Opera (chromium)
} else { 
   // not Opera (chromium) 
}

The new Opera 30 release now fully uses Chromium and also changed their userAgent to OPR

if(window.opera){
    //do stuffs, for example
    alert(opera.version()); //10.10 
}

No kidding, there is an object opera in opera browser.

You may think, object opera is overridable, but navigator is overridable too.

UPDATE:

To get more accurate result, you could do like

if (window.opera && opera.toString() == "[object Opera]"){
    //do stuffs, tested on opera 10.10
}

And I noticed, Opera have both addEventListener and attachEvent, so there is also another way like

if (window.addEventListener && window.attachEvent){
    //do stuffs, tested on opera 10.10
}