Possible Duplicate: JavaScript Variable Scope My understanding it that with in a function if I use var then I have a local variable. If I do not delcare var I now have a global variable. But what about oustide of functions, what effect does var have? First of all, it's generally bad practice to use code outside of functions. If nothing else, wrap your code in anonymous functions: (
可能重复: JavaScript变量范围 我的理解是,在一个函数中,如果我使用var,那么我有一个局部变量。 如果我不delcare var我现在有一个全局变量。 但是函数的尾巴呢,var有什么作用? 首先,在函数之外使用代码通常是不好的做法。 如果没有别的,请将您的代码包含在匿名函数中: (function(){ // code })(); 至于var有什么作用,它会“声明”一个变量: var foo; alert(foo); // undefined; VS: alert(foo); //
This question already has an answer here: What is the scope of variables in JavaScript? 25 answers The reason the second example works is because you're defining myvar as a global variable (which is accessible from anywhere). The first example doesn't work because the variable is defined within functional scope (meaning it's inaccessible from all except that function's scop
这个问题在这里已经有了答案: JavaScript中变量的范围是什么? 25个答案 第二个例子工作的原因是因为您将myvar定义为全局变量(可从任何地方访问)。 第一个例子不起作用,因为变量是在功能范围内定义的(这意味着除了该函数的作用域以外,所有函数都不可访问该变量,以及在该父函数范围内定义的函数范围)。 正如评论中所述,这只是JavaScript的工作原理。 如果这是您遇到的问题,那么现在可能是重新考虑您的架构的
How do you deep clone a Javascript object? I know there are various functions based on frameworks like JSON.parse(JSON.stringify(o)) and $.extend(true, {}, o) but I don't want to use a framework like that. What is the most elegant or efficient way to create a deep clone. We do care about edge cases like cloning array's. Not breaking prototype chains, dealing with self reference.
你如何深入克隆一个Javascript对象? 我知道有基于框架的各种功能,如JSON.parse(JSON.stringify(o))和$.extend(true, {}, o)但我不想使用这样的框架。 创建深度克隆的最优雅或有效的方式是什么? 我们确实关心像克隆数组这样的边缘情况。 不打破原型链,处理自我参照。 我们不关心支持DOM对象的复制等,因为.cloneNode存在。 由于我主要想在node.js使用深度克隆,因此使用V5引擎的ES5功能是可以接受的。 [编辑]
I want to use the Java API, HTMLUnit, to detect the number of eval() calls being called on the webpage by the JavaScript program. However, HTMLUnit doesn't have a built in handler for this type of JavaScript function. How can this be done? Thanks. Just an idea. Maybe you can inject a script with this code into the start of the html that you are loading: (function(){ const oldEval
我想使用Java API HTMLUnit来检测JavaScript程序在网页上调用的eval()调用的数量。 但是,HTMLUnit没有用于此类JavaScript函数的内置处理程序。 如何才能做到这一点? 谢谢。 只是一个想法。 也许你可以用这段代码将脚本注入到你正在加载的html的开头: (function(){ const oldEval = window.eval; window.eval = function () { // communicate here with your Java program that eval has been
I am developing a huge web site with a lot of images and animations. My problem is that the animations and the images take a lot of the available computing power of the browser and, sometimes, it can be saturated and just crash. So, I want to test the actual available computing power of the browser in order to know when I can display animations or load images. In the web, I find the Document
我正在开发一个包含大量图像和动画的巨大网站。 我的问题是,动画和图像占用了浏览器的大量可用计算能力,有时它可能会饱和并且只会崩溃。 所以,我想测试浏览器的实际可用计算能力,以了解何时可以显示动画或加载图像。 在网络中,我找到了Document.readyState方法,但它只给我一个信息:加载页面时,以及外部资源是否完全加载。 但是,浏览器可以绘制动画或加载其他外部资源... 我只想知道浏览器是否忙碌,如果我可以
Im using ngFacebook by Almog Baku in my current angular app. In test environment it is working fine. But in apk build via phonegap it isn't working. I have included <dependency id="cordova-plugin-inappbrowser" /> and <feature name="InAppBrowser"> <param name="android-package" value="org.apache.cordova.InAppBrowser" /> </feature> <feature name="InAp
我在当前的角度应用程序中使用Almog Baku的ngFacebook。 在测试环境中,它工作正常。 但是在通过phonegap构建的apk中不起作用。 我已包括在内 <dependency id="cordova-plugin-inappbrowser" /> 和 <feature name="InAppBrowser"> <param name="android-package" value="org.apache.cordova.InAppBrowser" /> </feature> <feature name="InAppBrowser"> <param name="ios-pac
For some reason I got stuck with this 'thing' As you can see I want to try to read the count.txt. This is working perfectly but for some reason the alert(code); is coming up after the alert("The number can't be smaler then 0"); For me it makes no sense because I'd call the alert(count) before the alert("The number...") Any ideas why the jQuery function (alert) is call
出于某种原因,我陷入了这个'事情' 正如你所看到的,我想尝试读取count.txt。 这工作完美,但出于某种原因 alert(code); 正在出现后 alert("The number can't be smaler then 0"); 对我来说,这是没有道理的,因为我会在alert(“数字...”) 之前调用alert(count)任何有关为什么在另一个alert后调用jQuery函数(alert)的想法? function leftFunction() { jQuery.get('count.txt', function(data) {
Given this JSON object: { "objects": { "foo": { "id": 1, "name": "Foo" }, "bar": { "id": 2, "name": "Bar" } } } This is an object containing sub objects where each sub object has the same structure - they're all the same type. Each sub-object is keyed uniquely, so it acts like a named array. I want to
鉴于这个JSON对象: { "objects": { "foo": { "id": 1, "name": "Foo" }, "bar": { "id": 2, "name": "Bar" } } } 这是一个包含子对象的对象,其中每个子对象具有相同的结构 - 它们都是相同的类型。 每个子对象的键都是唯一的,所以它就像一个命名数组。 我想验证objects属性中的每个对象是否针对JSON模式引用进行验证。 如果o
I have a process that sends me packets of data at intervals, and I need to manage that stream based on the timing of when the packets arrive and so on. At some point I also close the stream and the process. Right now, I'm using a set of timers to do this, but I hope I can do it with rxjs since it seems a very good fit for this kind of thing. So far, I haven't had much success. The p
我有一个进程每隔一段时间发送一次数据包,我需要根据数据包何时到达的时间来管理这个数据流,等等。 在某个时候,我也关闭了流和过程。 现在,我使用一组定时器来做到这一点,但我希望我可以用rxjs做到这一点,因为它似乎非常适合这种事情。 到目前为止,我还没有取得太多的成功。 问题 该流应该定期向我发送数据包,但它通常偏离很多,有时会卡住。 在下列情况下,我想在某个时候关闭流: 如果startDelay发送第一
I have a table cell that contains HTML, eg, <td id="test">something™ is here</td> I have an input field that I want to use to edit the HTML inside the table cell, eg, <input type="text" id="editor" value=""> I need to get the string something™ is here something™ is here from the table cell so I can put it into the <input> for edit
我有一个包含HTML的表格单元格,例如, <td id="test">something™ is here</td> 我有一个输入字段,我想用它来编辑表格单元格内的HTML,例如, <input type="text" id="editor" value=""> 我需要得到字符串的something™ is here something™ is here从表单元格,所以我可以把它放入<input>进行编辑。 我努力了 var txt=$("#test").text(); var htm=