casper.click("#selector")
casper.evaluate(function() { /*onclick function call*/ });
casper.sendKeys("#selector", casper.page.event.key.Enter);
casper.waitForPopup(/popup\.html$/, function() {
this.test.assertEquals(this.popups.length, 1);
});
casper.withPopup(/popup\.html$/, function() {
this.test.assertTitle('Popup title');
});