如何克服HTMLUnit ScriptException？
我遇到了一个代码行，可能会触发一些JS函数的问题，我怎么能解决这个问题？
box.setText(link.toString()); client.waitForBackgroundJavaScriptStartingBefore(10000); box.dblClick(); //this line cause the exception Exception in thread "main" ======= EXCEPTION START ======== EcmaError: lineNumber=[0] column=[0] lineSource=[function () {] name=[ReferenceError] sourceName=[onclick event for HtmlDivision[<div class="_119 stat_elem focus_target mtm mbl _5bsm _6dh _51z6" id="u_0_k" data-location="maincolumn" onclick="Bootloader.loadComponents("ComposerXControllerBootload", emptyFunction);">] in https://www.facebook.com/?_fb_noscript=1] message=[ReferenceError: "Bootloader" is not defined.] com.gargoylesoftware.htmlunit.ScriptException: ReferenceError: "Bootloader" is not defined. at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$HtmlUnitContextAction.run(JavaScriptEngine.java:684) at net.sourceforge.htmlunit.corejs.javascript.Context.call(Context.java:602) at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.call(ContextFactory.java:507) at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.callFunction(JavaScriptEngine.java:616) at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.callFunction(JavaScriptEngine.java:591) at com.gargoylesoftware.htmlunit.html.HtmlPage.executeJavaScriptFunctionIfPossible(HtmlPage.java:985) at com.gargoylesoftware.htmlunit.javascript.host.EventListenersContainer.executeEventHandler(EventListenersContainer.java:210) at com.gargoylesoftware.htmlunit.javascript.host.EventListenersContainer.executeBubblingListeners(EventListenersContainer.java:230) at com.gargoylesoftware.htmlunit.javascript.host.Node.fireEvent(Node.java:804) at com.gargoylesoftware.htmlunit.javascript.host.Node.fireEvent(Node.java:738) at com.gargoylesoftware.htmlunit.html.HtmlElement$1.run(HtmlElement.java:869) at net.sourceforge.htmlunit.corejs.javascript.Context.call(Context.java:602) at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.call(ContextFactory.java:507) at com.gargoylesoftware.htmlunit.html.HtmlElement.fireEvent(HtmlElement.java:874) at com.gargoylesoftware.htmlunit.html.HtmlElement.doClickFireClickEvent(HtmlElement.java:1311) at com.gargoylesoftware.htmlunit.html.HtmlElement.click(HtmlElement.java:1253) at com.gargoylesoftware.htmlunit.html.HtmlElement.click(HtmlElement.java:1205) at com.gargoylesoftware.htmlunit.html.HtmlElement.dblClick(HtmlElement.java:1351) at com.gargoylesoftware.htmlunit.html.HtmlElement.dblClick(HtmlElement.java:1326) at prototype.Profile.postLinkOnWall(Profile.java:225) at html.Log.findNext(Log.java:150) at prototype.Prtp.main(Prtp.java:49) Caused by: net.sourceforge.htmlunit.corejs.javascript.EcmaError: ReferenceError: "Bootloader" is not defined. at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3603) at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3587) at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.notFoundError(ScriptRuntime.java:3657) at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.nameOrFunction(ScriptRuntime.java:1749) at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.name(ScriptRuntime.java:1690) at net.sourceforge.htmlunit.corejs.javascript.Interpreter.interpretLoop(Interpreter.java:1622) at net.sourceforge.htmlunit.corejs.javascript.Interpreter.interpret(Interpreter.java:798) at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.call(InterpretedFunction.java:105) at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.doTopCall(ContextFactory.java:405) at com.gargoylesoftware.htmlunit.javascript.HtmlUnitContextFactory.doTopCall(HtmlUnitContextFactory.java:309) at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:3031) at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.call(InterpretedFunction.java:103) at com.gargoylesoftware.htmlunit.javascript.host.EventHandler.call(EventHandler.java:81) at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$4.doRun(JavaScriptEngine.java:609) at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$HtmlUnitContextAction.run(JavaScriptEngine.java:669) ... 21 more Enclosed exception: net.sourceforge.htmlunit.corejs.javascript.EcmaError: ReferenceError: "Bootloader" is not defined. at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3603) at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3587) at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.notFoundError(ScriptRuntime.java:3657) at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.nameOrFunction(ScriptRuntime.java:1749) at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.name(ScriptRuntime.java:1690) at net.sourceforge.htmlunit.corejs.javascript.Interpreter.interpretLoop(Interpreter.java:1622) at script.onclick(onclick event for HtmlDivision[<div class="_119 stat_elem focus_target mtm mbl _5bsm _6dh _51z6" id="u_0_k" data-location="maincolumn" onclick="Bootloader.loadComponents("ComposerXControllerBootload", emptyFunction);">] in https://www.facebook.com/?_fb_noscript=1) at net.sourceforge.htmlunit.corejs.javascript.Interpreter.interpret(Interpreter.java:798) at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.call(InterpretedFunction.java:105) at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.doTopCall(ContextFactory.java:405) at com.gargoylesoftware.htmlunit.javascript.HtmlUnitContextFactory.doTopCall(HtmlUnitContextFactory.java:309) at net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:3031) at net.sourceforge.htmlunit.corejs.javascript.InterpretedFunction.call(InterpretedFunction.java:103) at com.gargoylesoftware.htmlunit.javascript.host.EventHandler.call(EventHandler.java:81) at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$4.doRun(JavaScriptEngine.java:609) at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine$HtmlUnitContextAction.run(JavaScriptEngine.java:669) at net.sourceforge.htmlunit.corejs.javascript.Context.call(Context.java:602) at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.call(ContextFactory.java:507) at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.callFunction(JavaScriptEngine.java:616) at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.callFunction(JavaScriptEngine.java:591) at com.gargoylesoftware.htmlunit.html.HtmlPage.executeJavaScriptFunctionIfPossible(HtmlPage.java:985) at com.gargoylesoftware.htmlunit.javascript.host.EventListenersContainer.executeEventHandler(EventListenersContainer.java:210) at com.gargoylesoftware.htmlunit.javascript.host.EventListenersContainer.executeBubblingListeners(EventListenersContainer.java:230) at com.gargoylesoftware.htmlunit.javascript.host.Node.fireEvent(Node.java:804) at com.gargoylesoftware.htmlunit.javascript.host.Node.fireEvent(Node.java:738) at com.gargoylesoftware.htmlunit.html.HtmlElement$1.run(HtmlElement.java:869) at net.sourceforge.htmlunit.corejs.javascript.Context.call(Context.java:602) at net.sourceforge.htmlunit.corejs.javascript.ContextFactory.call(ContextFactory.java:507) at com.gargoylesoftware.htmlunit.html.HtmlElement.fireEvent(HtmlElement.java:874) at com.gargoylesoftware.htmlunit.html.HtmlElement.doClickFireClickEvent(HtmlElement.java:1311) at com.gargoylesoftware.htmlunit.html.HtmlElement.click(HtmlElement.java:1253) at com.gargoylesoftware.htmlunit.html.HtmlElement.click(HtmlElement.java:1205) at com.gargoylesoftware.htmlunit.html.HtmlElement.dblClick(HtmlElement.java:1351) at com.gargoylesoftware.htmlunit.html.HtmlElement.dblClick(HtmlElement.java:1326) at prototype.Profile.postLinkOnWall(Profile.java:225) at html.Log.findNext(Log.java:150) at prototype.Prtp.main(Prtp.java:49) == CALLING JAVASCRIPT == function () { [native code, arity=0] } ======= EXCEPTION END ======== 我写的那个盒子，在一个普通的浏览器上执行一个不能用HtmlUnit执行的重新格式化函数，所以我试着用dbclick（）强制它。
HtmlUnit不能很好的使用JavaScript。 它会经常抛出抱怨未定义的variables或函数的错误。
从这个意义上说， 现实生活中的浏览器（FireFox，Internet Explorer，Chrome等）更加灵活。 这意味着他们将允许语法不正确的HTML和JavaScript片断（例如：不定义函数或不结束HTML标记）。
HtmlUnit期望一切（几乎）完美。 虽然，它会修复一些缺less的结束HTML标签，一般来说，它期望页面中的代码不包含任何types的错误。 此外，即使一切看起来正确，HtmlUnit甚至可能会抱怨。
有些项目供您思考：
- 最重要的是在不同的
BrowserVersions之间切换。 您可以在创buildWebClient对象时设置它们。 Internet Explorer（具有讽刺意味的是）在解释JavaScript时已经certificate给我带来了最好的结果 - 确保你的HTML和JavaScript代码都是正确的
- 避免使用复杂的库（jQuery似乎得到了适当的支持）
- 尝试使用非最小化版本的库
- 如果碰巧使用jQuery（或其他类似的库），避免复杂的jQuery方法（例如：dynamic添加事件到元素）
当然，如果您能控制从服务器获取的源代码，那么这些评论就会适用。 有时候，事实并非如此。 在这种情况下，你的手甚至更多。
一种select是用下面的方法来抑制exception：
webClient.getOptions().setThrowExceptionOnScriptError(false);
虽然，这会让你通过例外不会纠正任何JavaScript错误。 这意味着如果引发这个exception的JS代码碰巧在你的逻辑中是至关重要的，那么你完全依赖于代码执行的结果，那么你不能让HtmlUnit处理你的JS。 如果这恰好是AJAX请求的结果，那么您可以手动发出请求，而不是让HtmlUnit这样做。
另一方面，如果给你麻烦的JS代码在你的逻辑中并不重要，我的意思是，它可能只是隐藏一个元素或者改变一个你不关心的颜色，然后抑制exception就是要走的路。
剩下的选项不多。
尝试设置您的Web客户端不要抛出exception：
client.getOptions().setThrowExceptionOnScriptError(false);
当我用方法得到一些网站时，我也遇到了同样的问题：
webClient.getPage("http://somepage.com");
如果你不需要使用JavaScript来处理网站，你可以写：
webClient.getOptions().setJavaScriptEnabled(false);
在我的情况下，它运作良好，脚本是立即执行（当我只使用webClient.getOptions().setThrowExceptionOnScriptError(false)然后脚本allways尝试执行糟糕的JavaScript代码，并在控制台写出exception消息约10秒，所以我不build议使用它）。
