javascript 主线程上的同步 XMLHttpRequest 已弃用

Synchronous XMLHttpRequest on the main thread is deprecated

提问by

• I am working on extjs framework..
  • i have an application running on extjs..
  • whenever i open the application in the browser...i see the following warnings in my console...

• 我正在研究 extjs 框架..
  • 我有一个在 extjs 上运行的应用程序。
  • 每当我在浏览器中打开应用程序时...我在控制台中看到以下警告...

Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check http://xhr.spec.whatwg.org/

主线程上的同步 XMLHttpRequest 已被弃用，因为它会对最终用户的体验产生不利影响。如需更多帮助，请查看http://xhr.spec.whatwg.org/

• can you guys tell me how to remove it..
• when i click the warning it takes to ext-all-debug-w-comments.js file

• and points to the following part of code...

  try { xhr.open('GET', noCacheUrl, false); xhr.send(null); } catch (e) { isCrossOriginRestricted = true; }

• can you guys tell me how to prevent it from happening...

• providing my code below in that file

  /** * Load a script file, supports both asynchronous and synchronous approaches * @private */ loadScriptFile: function(url, onLoad, onError, scope, synchronous) { if (isFileLoaded[url]) { return Loader; }

          var config = Loader.getConfig(),
              noCacheUrl = url + (config.disableCaching ? ('?' + config.disableCachingParam + '=' + Ext.Date.now()) : ''),
              isCrossOriginRestricted = false,
              xhr, status, onScriptError,
              debugSourceURL = "";
  
          scope = scope || Loader;
  
          Loader.isLoading = true;
  
          if (!synchronous) {
              onScriptError = function() {
              };
  
              scriptElements[url] = Loader.injectScriptElement(noCacheUrl, onLoad, onScriptError, scope);
          } else {
              if (typeof XMLHttpRequest != 'undefined') {
                  xhr = new XMLHttpRequest();
              } else {
                  xhr = new ActiveXObject('Microsoft.XMLHTTP');
              }
  
              try {
                  xhr.open('GET', noCacheUrl, false);
                  xhr.send(null);
              } catch (e) {
                  isCrossOriginRestricted = true;
              }
  
              status = (xhr.status === 1223) ? 204 :
                  (xhr.status === 0 && (self.location || {}).protocol == 'file:') ? 200 : xhr.status;
  
              isCrossOriginRestricted = isCrossOriginRestricted || (status === 0);
  
              if (isCrossOriginRestricted
              ) {
              }
              else if ((status >= 200 && status < 300) || (status === 304)
              ) {
                  // Debugger friendly, file names are still shown even though they're eval'ed code
                  // Breakpoints work on both Firebug and Chrome's Web Inspector
                  if (!Ext.isIE) {
                      debugSourceURL = "\n//@ sourceURL=" + url;
                  }
  
                  Ext.globalEval(xhr.responseText + debugSourceURL);
  
                  onLoad.call(scope);
              }
              else {
              }
  
              // Prevent potential IE memory leak
              xhr = null;
          }
      },
  

• 大佬能告诉我怎么去掉吗
• 当我单击 ext-all-debug-w-comments.js 文件的警告时

• 并指向以下代码部分...

  尝试 { xhr.open('GET', noCacheUrl, false); xhr.send(null); } catch (e) { isCrossOriginRestricted = true; }

• 你们能告诉我如何防止它发生吗...

• 在该文件中提供我的代码

  /** * 加载脚本文件，支持异步和同步两种方式 * @private */ loadScriptFile: function(url, onLoad, onError, scope, synchronous) { if (isFileLoaded[url]) { return Loader; } }

          var config = Loader.getConfig(),
              noCacheUrl = url + (config.disableCaching ? ('?' + config.disableCachingParam + '=' + Ext.Date.now()) : ''),
              isCrossOriginRestricted = false,
              xhr, status, onScriptError,
              debugSourceURL = "";
  
          scope = scope || Loader;
  
          Loader.isLoading = true;
  
          if (!synchronous) {
              onScriptError = function() {
              };
  
              scriptElements[url] = Loader.injectScriptElement(noCacheUrl, onLoad, onScriptError, scope);
          } else {
              if (typeof XMLHttpRequest != 'undefined') {
                  xhr = new XMLHttpRequest();
              } else {
                  xhr = new ActiveXObject('Microsoft.XMLHTTP');
              }
  
              try {
                  xhr.open('GET', noCacheUrl, false);
                  xhr.send(null);
              } catch (e) {
                  isCrossOriginRestricted = true;
              }
  
              status = (xhr.status === 1223) ? 204 :
                  (xhr.status === 0 && (self.location || {}).protocol == 'file:') ? 200 : xhr.status;
  
              isCrossOriginRestricted = isCrossOriginRestricted || (status === 0);
  
              if (isCrossOriginRestricted
              ) {
              }
              else if ((status >= 200 && status < 300) || (status === 304)
              ) {
                  // Debugger friendly, file names are still shown even though they're eval'ed code
                  // Breakpoints work on both Firebug and Chrome's Web Inspector
                  if (!Ext.isIE) {
                      debugSourceURL = "\n//@ sourceURL=" + url;
                  }
  
                  Ext.globalEval(xhr.responseText + debugSourceURL);
  
                  onLoad.call(scope);
              }
              else {
              }
  
              // Prevent potential IE memory leak
              xhr = null;
          }
      },
  

采纳答案by Lorenz Meyer

This warning is only showing in Chrome in the development environment of ExtJs. Once the application is built with sencha cmd, the warning doesn't show anymore. As @Evan pointed out the warning looks benign, and you should not have to worry about it.

此警告仅在 ExtJs 开发环境中的 Chrome 中显示。使用 构建应用程序后sencha cmd，警告不再显示。正如@Evan 指出的那样，警告看起来是良性的，您不必担心。

The fact that there is a warning should not be an issue, since it will never show in a deployed application. If you do not yet use sencha cmd, it is definitely worth to integrate it in your development cycle.

存在警告这一事实不应成为问题，因为它永远不会显示在已部署的应用程序中。如果您还没有使用 sencha cmd，那么将它集成到您​​的开发周期中绝对值得。

I know it is not a direct answer to the question. Myself, I wonder if it is possible to get rid of this warning at all.

我知道这不是问题的直接答案。我自己，我想知道是否有可能完全摆脱这个警告。