Questions tagged [javascript]

JavaScript (not to be confused with Java) is a high-level, dynamic, multi-paradigm, weakly-typed language used for both client-side and server-side scripting. Use this tag for questions regarding common implementations of ECMAScript, JavaScript, JScript, etc. JS does not typically refer to its ECMA-cousin, ActionScript.

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36
votes
5answers
23k views

How easy is it to hack JavaScript (in a browser)?

My question has to do with JavaScript security. Imagine an authentication system where you're using a JavaScript framework like Backbone or AngularJS, and you need secure endpoints. That's not a ...
36
votes
4answers
8k views

The importance of Design Patterns with Javascript, NodeJs et al

With Javascript appearing to be the ubiquitous programming language of the web over the next few years, new frameworks popping up every five minutes and event driven programming taking a lead both ...
35
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15answers
5k views

Should I continue my self-taught coding practice or learn how to do coding professionally? [closed]

Lately I've been getting professional work, hanging out with other programmers, and making friends in the industry. The only thing is I'm 100% self-taught. It's caused my style to extremely deviate ...
35
votes
10answers
9k views

Why aren't there other client-side scripting languages for websites? [closed]

Why is there just support for JavaScript and some VBScript in browsers today? I know JavaScript is good and all, but wouldn't having the option of using another programming language help promote ...
35
votes
5answers
15k views

Pros and cons of an HTML/JavaScript only web app [closed]

I come from an ASP.NET forms background and have found server side coding very powerful in the past. More recently, however, I have been wanting to phase out the server side code of the front-end and ...
34
votes
5answers
26k views

Is Javascript a Functional Programming Language

Is Javascript a functional language? I know it has objects & you can do OOP with it also, but is it also a functional language, can it be used in that way? You know how OOP became/seems like the ...
34
votes
8answers
23k views

When should JavaScript generate HTML?

I try to generate as little HTML from JavaScript as possible. Instead, I prefer to manipulate existing markup whenever I can and only generate HTML when I need to dynamically insert an element that ...
34
votes
3answers
20k views

Any point in using ES6 Map when keys are all strings?

Plain object keys must be strings, whereas a Map can have keys of any type. But I have little use for this in practice. In nearly all cases, I find myself using strings as keys anyway. And presumably ...
33
votes
14answers
13k views

What benefits are there to native JavaScript development? [closed]

Given how much simpler jQuery development is, when compared to native JavaScript, what makes people forgo libraries like jQuery altogether? Is this because jQuery has limitations or it is slow? I ...
33
votes
4answers
8k views

Does Dart have any useful features for web programmers?

http://www.dartlang.org/ I've checked out the site very briefly, and got curious. Is there any advantages of using Dart? Is it just a replacement for JavaScript? It looks like simpler Java. Writing ...
33
votes
6answers
40k views

How secure is localstorage?

The question says it all really. I want to provide a service but I do not want to store any of the data myself in a database. With all the recent news of hacking etc it seems to me that it is nicer ...
32
votes
14answers
3k views

Is it a common practice to minimize JavaScript usage when building a website? [closed]

I've been a web developer for almost 10 years and I've gotten into the habit of trying not to use JavaScript whenever possible. I'm not talking about building web apps here, but database driven ...
32
votes
5answers
7k views

Why do we need enums in dynamically typed languages?

I was reading some code here and saw that an enum is used to store names of html tags. Why do we ever need to do this? What benefit do I get using this strategy? I know that how useful enums are in ...
32
votes
10answers
7k views

Is it worth moving from Microsoft tech to Linux, NodeJS & other open source frameworks to save money for a start-up? [closed]

I am currently getting involved in a startup, I am the only developer involved at the moment, and the other guys are leaving all the tech decisions up to me at the moment. For my day job I work at a ...
32
votes
5answers
2k views

Why do code-bases in n-tier development have an equal amount of, if not more, JavaScript code now?

I've been doing web programming for a long time now, and somewhere, I lost track of why we are doing what we are doing today (or how did we come to do things this way)? I started out with basic ASP ...
32
votes
1answer
38k views

I know JavaScript really well, but i bomb coding interviews [closed]

So I'm currently on a hunt for a new position as a Front-End Developer. I know JavaScript very well and can wax poetically about Closures, Currying, Prototypal Inheritance, Design Patterns, App ...
32
votes
3answers
8k views

What does Douglas Crockford mean when he says jQuery doesn't scale? [closed]

In the Q&A section of this talk, Douglas Crockford says that jQuery doesn't scale as well as some other popular libraries. What does he mean by that, and what is it about the other libraries that ...
32
votes
7answers
2k views

Design Patterns for Javascript [duplicate]

A lot of web frameworks have a MVC-style layout to code and approaching problems. What are some good similar paradigms for JavaScript? I'm already using a framework (jQuery) and unobtrusive js, but ...
32
votes
1answer
15k views

Why should I use Bower? [closed]

I can fully appreciate the benefits of a package manager like Python's pip, Node's npm, or Ruby Gems since they're doing much more than adding files to your applications path. Maybe I'm missing the ...
31
votes
5answers
3k views

Javascript modularity, server based MVC & business reality

I understand this is a very broad question, but I have worked with various aspects of this problem individually and am struggling to bring all the concepts and technologies together. I'd like to ...
30
votes
8answers
15k views

Does comparing equality of float numbers mislead junior developers even if no rounding error occurs in my case?

For example, I want to show a list of buttons from 0,0.5,... 5, which jumps for each 0.5. I use a for loop to do that, and have different color at button STANDARD_LINE: var MAX=5.0; var DIFF=0.5 var ...
30
votes
6answers
5k views

Dynamic Code Evaluation in Java - Clever or Sloppy?

I am trying to create a flexible ACL framework in Java for my application. Many ACL frameworks are built on a whitelist of rules, where a rule is in the form of owner:action:resource. For example, "...
29
votes
8answers
7k views

Is splitting up a function into several inner functions an anti-pattern? [duplicate]

Imagine a long and complicated process, which is started by calling function foo(). There are several consecutive steps in this process, each of them depending on result of the previous step. The ...
29
votes
6answers
7k views

Should I place functions that are only used in one other function, within that function?

Specifically, I'm writing in JavaScript. Let's say my primary function is Function A. If Function A makes several calls to Function B, but Function B is not used anywhere else, then should I just ...
29
votes
2answers
116k views

How do I make a JavaScript promise return something other than a promise?

I have a spec from a client for an implementation of a method in a module: // getGenres(): // Returns a promise. When it resolves, it returns an array. If given an array of genres, ['comedy', '...
29
votes
1answer
1k views

What is the term for an anonymous JavaScript function that's called immediately?

I'm writing a JavaScript style-guide for my team, so that we can organise and contribute our documents easier. But I've hit a small bump which is where my question applies... What am I supposed to ...
29
votes
1answer
5k views

How is client-side javascript covered by the GPL?

If I used a GPL-licensed Javascript library in a web application, would I then have to offer source code of the whole site to anyone who downloaded and executed the Javascript lib?
28
votes
10answers
3k views

How does a programmer used to static languages cope with lack of Javascript tooling

I have programmed pretty much exclusively in compiled languages, particularly Java, for most of my career. One of my favourite things about Java is how productive you can be, and how little code you ...
28
votes
5answers
4k views

Tight Coupling Between Javascript, HTML, and CSS: A More Modern Approach?

It's very common to see Javascript bound to certain selectors to find elements, store data, and listen for events. It's also common to see these same selectors used for styling. jQuery (and its ...
28
votes
4answers
50k views

Function declaration as var instead of function

More and more I'm seeing functions being declared like var foo = function() { // things }; Instead of how I had learned, like function foo() { // things } What's the difference? Better ...
28
votes
2answers
24k views

Methods of separating front and back-end with full stack javascript?

Suppose I have a front-end which is mostly a single-page application written using angular, grunt, and bower. And suppose I have a backend, which is mostly just a REST API sitting on top of an ORM, ...
28
votes
2answers
2k views

Why does XMLHttpRequest not seem to follow a naming convention?

I've been working with the XMLHttpRequest object in JavaScript recently, and I couldn't help but notice that the casing of this name makes no sense. Why is 'XML' all in caps while 'Http' is not? ...
27
votes
12answers
8k views

How did JavaScript become popular?

In ancient history, Brendan Eich had a language design, and in today's world, JavaScript is a popular language implemented and used in many different places. What caused the language to become ...
27
votes
3answers
9k views

What functionality does WebStorm contain which RubyMine does not?

I am looking at buying Rubymine as I am doing a small amount of ruby, but a large amount of html5/javascript. I was going to get Webstorm as I do have a lot of pure html5/js based frameworks/apps ...
27
votes
3answers
18k views

Building web apps in server-side vs client-side vs hybrid? [closed]

There are currently multiple approaches for building web applications: 1. Server-side only This is a classical approach where you render pages on the server by a web framework like Ruby on Rails, ...
27
votes
2answers
10k views

What is ASM.js and what does it mean for everyone?

I'm starting to hear rumblings about this project called ASM.js. Currently their web site is terrible and confusing. Here's what I know from my research on the web. It is a subset of JavaScript that ...
27
votes
3answers
19k views

Dealing with browser cache in single-page apps

I'm trying to figure out how to properly handle the web browser cache for single page apps. I have a fairly typical design: several HTML, JS and CSS files implementing the SPA, and a bunch of JSON ...
26
votes
9answers
2k views

Ashamed to admit using jQuery? [closed]

Something I've noticed over the past few weeks is how many big commercial websites use jQuery combined with lots of plugins - but don't admit it. They will rename the main library to something obscure,...
26
votes
2answers
23k views

How does Javascript code become asynchronous when using callbacks?

I've been doing a lot of reading online trying to figure out how to write asynchronous JavaScript code. One of the techniques that has come up a lot in my research is to use callbacks. While I ...
26
votes
11answers
6k views

Is javascript worth learning if you do not plan on being a web developer?

I heard Javascript is a full language just like c++. Is this true? What else is it good for programming besides web stuff?
26
votes
7answers
21k views

Self-Executing Anonymous Function vs Prototype

In Javascript there are a few clearly prominent techniques for create and manage classes/namespaces in javascript. I am curious what situations warrant using one technique vs. the other. I want to ...
26
votes
2answers
2k views

Why is passing large anonymous functions as arguments to other functions so widely accepted in JavaScript?

I have an opinion (which I am sure will be shared by some) that passing anonymous functions which contain more than a few lines of code, as arguments to other functions affects readability and self-...
26
votes
4answers
15k views

What determines which Javascript functions are blocking vs non-blocking?

I have been doing web-based Javascript (vanilla JS, jQuery, Backbone, etc.) for a few years now, and recently I've been doing some work with Node.js. It took me a while to get the hang of "non-...
25
votes
1answer
14k views

Is vanilla JS still considered a library?

I very recently found out that VanillaJS (document?) is a library that's just bundled with 99% browsers and isn't exactly native JavaScript (shock of my life). While writing a lib of my own I normally ...
25
votes
4answers
19k views

Why make the login page to a single page application a separate page?

I am wondering why it seems to be popular to have the login page of a SPA be a separate page that is not page of the SPA (as in loaded and send data through ajax requests)? I only thing I can think ...
25
votes
8answers
10k views

The importance of javascript and the best way to learn it? [duplicate]

I'm a new graduate, but I have been doing web development for about six months. When I was finishing university the server side languages (PHP, Java) were more important then client side languages. ...
25
votes
5answers
3k views

Is rejecting a Promise only for error cases?

Let's say I have this function authenticate that returns a promise. The promise then resolves with the result. False and true are expected outcomes, as I see it, and rejections should only occur in an ...
25
votes
1answer
4k views

A few clarifications about the DOM

I have been trying to understand the DOM, and although I have a fair idea of what it is, there are certain ideas I just cannot pin down. I will list down what I think the DOM is and my questions will ...
25
votes
1answer
4k views

The Box Model: Internet Explorer vs. W3C

Today, the Internet Explorer Box Model problem is mostly a non-issue. Most web developers place a <!DOCTYPE> tag to enforce standards compliance, and nobody really cares about supporting ...
24
votes
11answers
17k views

How necessary is it to learn JavaScript before jQuery? [closed]

In my opinion, when I looked at JavaScript, it looked like not my cup of tea. When I came across jQuery, I loved it. I sat and watched Nettuts+ 15 days of jQuery screencasts, 1 year later and now I'm ...