how to forcefully click on button in iframe using jquery or php.
example
<iframe src="www.google.com"></iframe>
i want to press the button or anchor tag in that iframe.
And also change anchor tag target -> '_self'
Expanding on "not possible"...
The "Same origin policies" apply: your only way of communicating with the contents of iframes that come from another [domain|subdomain|protocol|port] is through the postMessage API, which of course requires the other part (the document inside the iframe) to listen to your messages. This means that unless you're a google employee with access to the search frontend, this won't be possible.
If you work at google and want to press a button forcefully, I recommend standing with your foot on your mouse: your weight will help push it with more strength.
Not possible. Blocked by Browsers for security concerns.
On serverside you could use CasperJS to click some stuff inside an iFrame. See here How do I access an iframe from CasperJS?