摘要：
WebViewController_控制器；onWebViewCreated:（WebViewControllervc）｛_controller=wvc；｝onPageFinished：（Stringvalue）｛_controller.avaluateJavascript（'document.coook=“SESSIONID=612bc4822b6996d6f335a963c2
WebViewController _controller;
onWebViewCreated: (WebViewController wvc) {
_controller = wvc;
}
onPageFinished: (String value) {
_controller.evaluateJavascript( 'document.cookie = "SESSIONID=612bc4822b6996d6f335a963c20eb541fba72985; path=/"')
}
设置cookies需要注意时机，这里是在页面加载完成后才设置cookie