blocks|key|73395|text|无法获取上下文，因为布局和javascript是在另一个进程上处理的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|73396|相反，将脚本添加到您的webview配置中，并将视图控制器(或其他对象)设置为脚本消息处理程序。|73397|现在，从JavaScript发送消息，如下所示：|73398|window.webkit.messageHandlers.interOp.postMessage(message)|code-block|syntax|javascript|73399|您的脚本消息处理程序将收到回调：|73400|-+(void)userContentController:(WKUserContentController+*)userContentController+
++++++++++++++++++++++++++++didReceiveScriptMessage:(WKScriptMessage+*)message{
++++NSLog(@"%25@",+message.body);
}|73401|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|S|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|T|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|H|7|V|8|@]|9|@]|A|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

You cannot obtain the context, because layout and javascript is handled on another process.

Instead, add scripts to your webview configuration, and set your view controller (or another object) as the script message handler.

Now, send messages from JavaScript like so:

<pre><code>window.webkit.messageHandlers.interOp.postMessage(message)
</code></pre>

Your script message handler will receive a callback:

<pre><code>- (void)userContentController:(WKUserContentController *)userContentController 
 didReceiveScriptMessage:(WKScriptMessage *)message{
 NSLog(@"%@", message.body);
}
</code></pre>

blocks|key|73430|text|像这样配置您的wkwebview，并相应地添加处理程序，并以类似的模式从脚本中发布消息|type|unstyled|depth|inlineStyleRanges|entityRanges|data|73431|NSString+*myScriptSource+=+@"alert('Hello,+World!')";


WKUserScript+*s+=+[[WKUserScript+alloc]+initWithSource:myScriptSource+injectionTime:WKUserScriptInjectionTimeAtDocumentStart+forMainFrameOnly:YES];
WKUserContentController+*c+=+[[WKUserContentController+alloc]+init];
[c+addUserScript:s];
//+Add+a+script+message+handler+for+receiving++"buttonClicked"+event+notifications+posted+from+the+JS+document+using+window.webkit.messageHandlers.buttonClicked.postMessage+script+message
[c+addScriptMessageHandler:self+name:@"buttonClicked"];

WKWebViewConfiguration+*conf+=+[[WKWebViewConfiguration+alloc]+init];
conf.userContentController+=+c;

WKWebView+*webview+=+[[WKWebView+alloc]+initWithFrame:self.view.bounds+configuration:conf];
[self.view+addSubview:webview];
webview.autoresizingMask+=+UIViewAutoresizingFlexibleWidth+%7C+UIViewAutoresizingFlexibleHeight;
//+Do+any+additional+setup+after+loading+the+view,+typically+from+a+nib.
NSURLRequest+*request+=+[NSURLRequest+requestWithURL:[NSURL+URLWithString:@"http://google.com"]];
[webview+loadRequest:request];|code-block|syntax|javascript|73432|使用方法名实现脚本消息处理程序"WKScriptMessageHandler“|73433|#pragma+mark+-WKScriptMessageHandler
-+(void)userContentController:(WKUserContentController+*)userContentController+didReceiveScriptMessage:(WKScriptMessage+*)message++++++++++{
if+([message.name+isEqualToString:@"buttonClicked"])+{
self.buttonClicked+%2B%2B;
}

//+JS+objects+are+automatically+mapped+to+ObjC+objects
id+messageBody+=+message.body;
if+([messageBody+isKindOfClass:[NSDictionary+class]])+{
NSString*+idOfTappedButton+=+messageBody[@"ButtonId"];
[self+updateColorOfButtonWithId:idOfTappedButton];
}
}|73434|并发布消息表单js，如下所示|73435|var+button+=+document.getElementById("clickMeButton");
button.addEventListener("click",+function()+{
++++var+messgeToPost+=+{'ButtonId':'clickMeButton'};
++++window.webkit.messageHandlers.buttonClicked.postMessage(messgeToPost);
},false);|73436|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

configure your wkwebview like this and add handler accordingly and post message from script in similar pattern

<pre><code>NSString *myScriptSource = @"alert('Hello, World!')";


WKUserScript *s = [[WKUserScript alloc] initWithSource:myScriptSource injectionTime:WKUserScriptInjectionTimeAtDocumentStart forMainFrameOnly:YES];
WKUserContentController *c = [[WKUserContentController alloc] init];
[c addUserScript:s];
// Add a script message handler for receiving "buttonClicked" event notifications posted from the JS document using window.webkit.messageHandlers.buttonClicked.postMessage script message
[c addScriptMessageHandler:self name:@"buttonClicked"];

WKWebViewConfiguration *conf = [[WKWebViewConfiguration alloc] init];
conf.userContentController = c;

WKWebView *webview = [[WKWebView alloc] initWithFrame:self.view.bounds configuration:conf];
[self.view addSubview:webview];
webview.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
// Do any additional setup after loading the view, typically from a nib.
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://google.com"]];
[webview loadRequest:request];
</code></pre>

implement script message handler "WKScriptMessageHandler" with method name

<pre><code>#pragma mark -WKScriptMessageHandler
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message {
if ([message.name isEqualToString:@"buttonClicked"]) {
self.buttonClicked ++;
}

// JS objects are automatically mapped to ObjC objects
id messageBody = message.body;
if ([messageBody isKindOfClass:[NSDictionary class]]) {
NSString* idOfTappedButton = messageBody[@"ButtonId"];
[self updateColorOfButtonWithId:idOfTappedButton];
}
}
</code></pre>

and post the message form js like this

<pre><code>var button = document.getElementById("clickMeButton");
button.addEventListener("click", function() {
 var messgeToPost = {'ButtonId':'clickMeButton'};
 window.webkit.messageHandlers.buttonClicked.postMessage(messgeToPost);
},false);
</code></pre>

In UIWebView, I can get <code>JSContext</code> through:

<pre><code>[webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"]
</code></pre>

The same way doesn't work in WKWebView and app crashes when it arrives this line of code.

Is there a way to get JSContext in WKWebView?

thanks in advance.

How to get JSContext from WKWebView

在UIWebView中，我可以让JSContext通过：[webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"]同样的方式在WKWebView中不起作用，当应用程序到达这行代码时就会崩溃。有没有办法在WKWebView中使...

问如何从WKWebView获取JSContext
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