iOS8開始使用WKWebView，但實際使用過程中和UIWebView有許多區別。比如禁止在webview中長按彈出UIMenuController的操作：

• UIWebView中

 - (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
    return NO;
}

• WKWebView中，則需要通過js進行操作

// 禁止選擇CSS
NSString *css = @"body{-webkit-user-select:none;-webkit-user-drag:none;}";

// CSS選中樣式取消
 

NSMutableString *javascript = [NSMutableString string];
[javascript appendString:@"var style = document.createElement('style');"];
[javascript appendString:@"style.type = 'text/css';"];
[javascript appendFormat:@"var cssContent = document.createTextNode('%@');", css];
[javascript appendString:@"style.appendChild(cssContent);"
 
];
[javascript appendString:@"document.body.appendChild(style);"];

// javascript注入
WKUserScript *noneSelectScript = [[WKUserScript alloc] initWithSource:javascript injectionTime:WKUserScriptInjectionTimeAtDocumentEnd forMainFrameOnly:YES];
WKUserContentController *userContentController = [[WKUserContentController alloc] init];
[userContentController addUserScript:noneSelectScript];
WKWebViewConfiguration *configuration = [[WKWebViewConfiguration alloc] init];
configuration.userContentController
 
 = userContentController;

// WKWebView 初始化
WKWebView *webView = [[WKWebView alloc] initWithFrame:frame configuration:configuration];

另外提一句，獲取webView當前選中的內容方法：

NSString *highlighted = [_webView stringByEvaluatingJavaScriptFromString:@"window.getSelection().toString();"];