How to get a page's title which in iframe?

first I have a simple iframe

<iframe src="http://www.google.com"></iframe>

I also have a button to alert the google's title

<input type="button" value="gettitle" />

then I want use jquery to get the iframe inner html's title

开发者_Go百科    $("input ").click(function () {
        alert($('iframe').contents().find("title").text());
    });

But it doesn't work,what's wrong with this code?How can I get the title correctly?

Here the online case

Thank you

Same origin policy will prevent you from doing that if the page in your <iframe> element doesn't come from the same domain as your main page. Since your example uses www.google.com, it won't work.

That said, your code is correct and should work as expected when the two pages come from the same domain.

see http://jsfiddle.net/TAtQT/7/