Javascript WKWebviewevaluateJavascript 不工作，抛出错误
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WKWebview evaluateJavascript is not working, throws an error
提问by Rogers Sampaio
I am trying to call an existent function from a remote site in a WKWebview:
我正在尝试从 WKWebview 中的远程站点调用现有函数：
function addtext (text) {
jQuery("#webviewtest").html(text);
}
With:
和：
[self.WebView evaluateJavaScript:@"addtext(\"This is a text from app\");" completionHandler:^(id Result, NSError * error) {
NSLog(@"Error -> %@", error);
}];
But this is throwing an error:
但这会引发错误：
Error Domain=WKErrorDomain Code=4 "A JavaScript exception occurred" UserInfo=0x170c788c0 {NSLocalizedDescription=A JavaScript exception occurred}
This is so simple! I am must missing something really stupid!
这太简单了！我一定错过了一些非常愚蠢的东西！
回答by Rogers Sampaio
Found a solution, it was simple as I was expecting, I was adding the javascript before the view complete load the content (before the Dom Ready). So I just had to move my code to the delegate method below:
找到了一个解决方案，它很简单，正如我所期望的，我在视图完成加载内容之前（在 Dom Ready 之前）添加了 javascript。所以我只需要将我的代码移动到下面的委托方法：
- webView:didFinishNavigation: (from WKNavigationDelegate)
- webView:didFinishNavigation: (来自WKNavigationDelegate)
I hope this helps someone.
我希望这可以帮助别人。
回答by UKDataGeek
I found that the problem was caused by the webView:didFinishNavigation:being called before the page content was actually loaded. I think the website is using angularjs.
我发现问题是由于webView:didFinishNavigation:在实际加载页面内容之前被调用造成的。我认为该网站正在使用 angularjs。
I introduced a manual delay which seemed to d the trick for me :
我引入了一个手动延迟，这对我来说似乎是个窍门：
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
print("loaded)")
//abtn_run(UIButton())
self.perform(#selector(performAction), with: nil, afterDelay: 3.0)
}
and did my call here:
并在这里打了电话：
func performAction() {
//This function will perform this after delay of 3 seconds
}
Ideally the best solution would have a listener push an event for angularjs "page ready" but I am not sure this is possible in wkwebview.
理想情况下，最好的解决方案是让侦听器为 angularjs“页面就绪”推送一个事件，但我不确定这在 wkwebview 中是否可行。
