复杂的错误处理

如果你的错误处理非常复杂，因此可能会抛出一个错误本身，添加一个标志来表明你是否已经在“errorHandling-Mode”是很有用的。像这样:

var appIsHandlingError = false;

window.onerror = function() {
    if (!appIsHandlingError) {
        appIsHandlingError = true;
        handleError();
    }
};

function handleError() {
    // graceful error handling
    // if successful: appIsHandlingError = false;
}

否则你会发现自己陷入了一个无限循环。

你可以通过给window.onerror赋值函数来监听onerror事件:

 window.onerror = function (msg, url, lineNo, columnNo, error) {
        var string = msg.toLowerCase();
        var substring = "script error";
        if (string.indexOf(substring) > -1){
            alert('Script Error: See Browser Console for Detail');
        } else {
            alert(msg, url, lineNo, columnNo, error);
        }   
      return false; 
  };

似乎是那个窗口。Onerror不提供对所有可能错误的访问。具体来说，它忽略了:

<img>加载错误(响应>= 400)。 <脚本>加载错误(响应>= 400)。 如果你的应用程序中有许多其他库也在操纵窗口，则会出现全局错误。以未知的方式出现Onerror (jquery, angular等)。 可能在探索这个之后，我还没有遇到很多情况(iframes，堆栈溢出等)。

下面是一个脚本的开头，它可以捕捉到很多这样的错误，这样你就可以在开发过程中为你的应用程序添加更健壮的调试。

(function(){

/**
 * Capture error data for debugging in web console.
 */

var captures = [];

/**
 * Wait until `window.onload`, so any external scripts
 * you might load have a chance to set their own error handlers,
 * which we don't want to override.
 */

window.addEventListener('load', onload);

/**
 * Custom global function to standardize 
 * window.onerror so it works like you'd think.
 *
 * @see http://www.quirksmode.org/dom/events/error.html
 */

window.onanyerror = window.onanyerror || onanyerrorx;

/**
 * Hook up all error handlers after window loads.
 */

function onload() {
  handleGlobal();
  handleXMLHttp();
  handleImage();
  handleScript();
  handleEvents();
}

/**
 * Handle global window events.
 */

function handleGlobal() {
  var onerrorx = window.onerror;
  window.addEventListener('error', onerror);

  function onerror(msg, url, line, col, error) {
    window.onanyerror.apply(this, arguments);
    if (onerrorx) return onerrorx.apply(null, arguments);
  }
}

/**
 * Handle ajax request errors.
 */

function handleXMLHttp() {
  var sendx = XMLHttpRequest.prototype.send;
  window.XMLHttpRequest.prototype.send = function(){
    handleAsync(this);
    return sendx.apply(this, arguments);
  };
}

/**
 * Handle image errors.
 */

function handleImage() {
  var ImageOriginal = window.Image;
  window.Image = ImageOverride;

  /**
   * New `Image` constructor. Might cause some problems,
   * but not sure yet. This is at least a start, and works on chrome.
   */

  function ImageOverride() {
    var img = new ImageOriginal;
    onnext(function(){ handleAsync(img); });
    return img;
  }
}

/**
 * Handle script errors.
 */

function handleScript() {
  var HTMLScriptElementOriginal = window.HTMLScriptElement;
  window.HTMLScriptElement = HTMLScriptElementOverride;

  /**
   * New `HTMLScriptElement` constructor.
   *
   * Allows us to globally override onload.
   * Not ideal to override stuff, but it helps with debugging.
   */

  function HTMLScriptElementOverride() {
    var script = new HTMLScriptElement;
    onnext(function(){ handleAsync(script); });
    return script;
  }
}

/**
 * Handle errors in events.
 *
 * @see http://stackoverflow.com/questions/951791/javascript-global-error-handling/31750604#31750604
 */

function handleEvents() {
  var addEventListenerx = window.EventTarget.prototype.addEventListener;
  window.EventTarget.prototype.addEventListener = addEventListener;
  var removeEventListenerx = window.EventTarget.prototype.removeEventListener;
  window.EventTarget.prototype.removeEventListener = removeEventListener;

  function addEventListener(event, handler, bubble) {
    var handlerx = wrap(handler);
    return addEventListenerx.call(this, event, handlerx, bubble);
  }

  function removeEventListener(event, handler, bubble) {
    handler = handler._witherror || handler;
    removeEventListenerx.call(this, event, handler, bubble);
  }

  function wrap(fn) {
    fn._witherror = witherror;

    function witherror() {
      try {
        fn.apply(this, arguments);
      } catch(e) {
        window.onanyerror.apply(this, e);
        throw e;
      }
    }
    return fn;
  }
}

/**
 * Handle image/ajax request errors generically.
 */

function handleAsync(obj) {
  var onerrorx = obj.onerror;
  obj.onerror = onerror;
  var onabortx = obj.onabort;
  obj.onabort = onabort;
  var onloadx = obj.onload;
  obj.onload = onload;

  /**
   * Handle `onerror`.
   */

  function onerror(error) {
    window.onanyerror.call(this, error);
    if (onerrorx) return onerrorx.apply(this, arguments);
  };

  /**
   * Handle `onabort`.
   */

  function onabort(error) {
    window.onanyerror.call(this, error);
    if (onabortx) return onabortx.apply(this, arguments);
  };

  /**
   * Handle `onload`.
   *
   * For images, you can get a 403 response error,
   * but this isn't triggered as a global on error.
   * This sort of standardizes it.
   *
   * "there is no way to get the HTTP status from a 
   * request made by an img tag in JavaScript."
   * @see http://stackoverflow.com/questions/8108636/how-to-get-http-status-code-of-img-tags/8108646#8108646
   */

  function onload(request) {
    if (request.status && request.status >= 400) {
      window.onanyerror.call(this, request);
    }
    if (onloadx) return onloadx.apply(this, arguments);
  }
}

/**
 * Generic error handler.
 *
 * This shows the basic implementation, 
 * which you could override in your app.
 */

function onanyerrorx(entity) {
  var display = entity;

  // ajax request
  if (entity instanceof XMLHttpRequest) {
    // 400: http://example.com/image.png
    display = entity.status + ' ' + entity.responseURL;
  } else if (entity instanceof Event) {
    // global window events, or image events
    var target = entity.currentTarget;
    display = target;
  } else {
    // not sure if there are others
  }

  capture(entity);
  console.log('[onanyerror]', display, entity);
}

/**
 * Capture stuff for debugging purposes.
 *
 * Keep them in memory so you can reference them
 * in the chrome debugger as `onanyerror0` up to `onanyerror99`.
 */

function capture(entity) {
  captures.push(entity);
  if (captures.length > 100) captures.unshift();

  // keep the last ones around
  var i = captures.length;
  while (--i) {
    var x = captures[i];
    window['onanyerror' + i] = x;
  }
}

/**
 * Wait til next code execution cycle as fast as possible.
 */

function onnext(fn) {
  setTimeout(fn, 0);
}

})();

它可以这样使用:

window.onanyerror = function(entity){
  console.log('some error', entity);
};

完整的脚本有一个默认实现，它尝试打印出它接收到的实体/错误的半可读的“显示”版本。可以为特定于应用程序的错误处理程序提供灵感。默认实现还保留了对最后100个错误实体的引用，所以你可以在它们发生后在web控制台中检查它们:

window.onanyerror0
window.onanyerror1
...
window.onanyerror99

注意:这是通过覆盖几个浏览器/本地构造函数上的方法来实现的。这可能会产生意想不到的副作用。然而，在开发过程中使用它，找出错误发生的位置，在开发过程中向NewRelic或Sentry等服务发送日志，这样我们就可以在开发过程中测量错误，在阶段中，我们可以在更深层次上调试正在发生的事情。然后可以在生产环境中关闭它。

希望这能有所帮助。

如何捕捉未处理的Javascript错误

分配窗口。Onerror事件到事件处理程序，如:

<script type="text/javascript">
window.onerror = function(msg, url, line, col, error) {
   // Note that col & error are new to the HTML 5 spec and may not be 
   // supported in every browser.  It worked for me in Chrome.
   var extra = !col ? '' : '\ncolumn: ' + col;
   extra += !error ? '' : '\nerror: ' + error;

   // You can view the information in an alert to see things working like this:
   alert("Error: " + msg + "\nurl: " + url + "\nline: " + line + extra);

   // TODO: Report this error via ajax so you can keep track
   //       of what pages have JS issues

   var suppressErrorAlert = true;
   // If you return true, then error alerts (like in older versions of 
   // Internet Explorer) will be suppressed.
   return suppressErrorAlert;
};
</script>

如代码中所示，如果返回window的值。如果Onerror为真，则浏览器应该抑制显示警报对话框。

窗户什么时候开。onerror事件火灾?

简而言之，当1.)存在未捕获的异常或2.)发生编译时错误时引发该事件。

未捕获异常 抛出“一些信息” call_something_undefined (); ，一个安全异常 编译错误 <脚本>{> < /脚本 < >脚本(,)> < /脚本 < >脚本”哦> < /脚本 setTimeout("{"， 10);，它将尝试将第一个参数编译为 一个脚本

浏览器支持window.onerror

铬13 + Firefox 6.0 + Internet Explorer 5.5+ Opera 11.60 + Safari 5.1 +

截图:

上面的onerror代码在添加到测试页面后起作用的例子:

<script type="text/javascript">
call_something_undefined();
</script>

AJAX错误报告示例

var error_data = {
    url: document.location.href,
};

if(error != null) {
    error_data['name'] = error.name; // e.g. ReferenceError
    error_data['message'] = error.line;
    error_data['stack'] = error.stack;
} else {
    error_data['msg'] = msg;
    error_data['filename'] = filename;
    error_data['line'] = line;
    error_data['col'] = col;
}

var xhr = new XMLHttpRequest();

xhr.open('POST', '/ajax/log_javascript_error');
xhr.setRequestHeader('X-Requested-With', 'XMLHttpRequest');
xhr.setRequestHeader('Content-Type', 'application/json');
xhr.onload = function() {
    if (xhr.status === 200) {
        console.log('JS error logged');
    } else if (xhr.status !== 200) {
        console.error('Failed to log JS error.');
        console.error(xhr);
        console.error(xhr.status);
        console.error(xhr.responseText);
    }
};
xhr.send(JSON.stringify(error_data));

JSFiddle:

https://jsfiddle.net/nzfvm44d/

引用:

Mozilla开发者网络::window.onerror 处理和避免网页错误第2部分:运行时错误 返回基础- JavaScript onerror事件 window.onerror可以更好地处理错误 Window onError事件 使用onerror事件来抑制JavaScript错误 SO:: window。在Firefox中未启动onerror

这对你有帮助吗:

<script type="text/javascript">
window.onerror = function() {
    alert("Error caught");
};

xxx();
</script>

我不确定它是如何处理Flash错误的…

更新:它不能在Opera中工作，但我现在正在黑蜻蜓，看看它能得到什么。关于破解蜻蜓的建议来自这个问题:

模拟窗口。onerror在Opera使用javascript

还应该保留之前关联的onerror回调

<script type="text/javascript">

(function() {
    var errorCallback = window.onerror;
    window.onerror = function () {
        // handle error condition
        errorCallback && errorCallback.apply(this, arguments);
    };
})();

</script>