I'm pretty efficient in jQuery, having implementing it in several projects for my company. However, I found myself a little lost when reading stuff like node.js.

Do I have to go back to basics and learn the JavaScript language or should I just stick with jQuery?

One more thing I would like to ask: Does coding in plain JavaScript increase performance compared to coding with jQuery? For my own experience, coding heavy, complex combination of animation in jQuery always seems to take up large amount of the computer memory.

I'm pretty efficient in jQuery, having implementing it in several projects for my company. However, I found myself a little lost when reading stuff like node.js.

Do I have to go back to basics and learn the JavaScript language or should I just stick with jQuery?

One more thing I would like to ask: Does coding in plain JavaScript increase performance compared to coding with jQuery? For my own experience, coding heavy, complex combination of animation in jQuery always seems to take up large amount of the computer memory.

• javascript
• jquery

• 6 You at least know that there is a difference, unlike many others. – Dykam Commented May 15, 2010 at 9:27
• for your second question: it is faster writing in plain javascript, if you know what you're doing. Libraries try to optimize for speed, but there will always be a performance cost of being abstract. – gblazex Commented Jun 29, 2010 at 2:49
• If you are good at Javascript then you know it would be "Being good in jQuery === Being good in Javascript". At least that is this books recommendation amazon.com/JavaScript-Good-Parts-Douglas-Crockford/dp/… – Christopher Altman Commented Nov 7, 2010 at 0:53

8 Answers 8

You should understand what's going on, to a degree. It doesn't hurt to know what's underneath, but sometimes that's not optimal to know everything either, for example: is .innerHTML consistent? Not completely, e.g. <select> in IE. Does that mean you need to know every inconsistency? Not if you're letting jQuery handle it.

People say you need to understand JavaScript before jQuery, let me say I agree, however there are limits to that though, you don't necessarily need to know every quirk and inconsistency between browsers for example, that's why we use an abstraction layer.

To me, this is no different than saying you need to learn assembly before C#, should you know what's happening, how memory is referenced, what a pointer is? I think so, do you need to know every detail? Probably not. We would never progress if every new programmer goes through learning every layer beneath, this is why math theorems build upon others known to be true, same concept.

You should be able to trust your abstraction layer. Is this always true? unfortunately not, but jQuery does a pretty good job at being as consistent as possible and always improving. More importantly, the community does a good job of making the inconsistencies known.

Edit: Let me caveat everything above by saying if you can learn what's underneath do so (this applies to most any abstraction in my book, not just JavaScript), it will help you program better and more efficiently. If you know what's going on under the covers, you can more optimally take advantage of it.

It's a lot like apples and oranges, actually. jQuery is awesome library but it focuses on DOM manipulations. It does not help you much with general coding, prototype inheritance, closures, data types and other important stuff you have to deal with when programming.

node.js have nothing to do with DOM, so it is very much orthogonal to jQuery, no wonder you have trouble understanding it.

Note, however, that knowledge of JavaScript won't necessarily mean you'll be efficient with every JavaScript library out there. Each library makes kind of a superset of a language, a domain specific language to help with specific task that library was built to solve. You will always have to learn that DSL first to be efficient but it'll be easier to understand internals of any given library if you know JavaScript well.

If you are only interested in application programming (web sites and applications) then jQuery is more than adequate. If you want to develop a JavaScript framework or library, then proficient knowledge of the JavaScript language is necessary.

Does being good in jQuery imply being good in JavaScript?

No. I strongly suggest you learn the basics and then some.

jQuery is just a library. While productive, being well versed in the functionality that a library provides is not the same as being good at the language in which that library is written in.

I'm not saying that you need to know that all bitwise operations are converted to signed 32-bit integers in big-endian order, but you do need to know about core concepts like closures, how to properly attach event handlers, and the basic concepts of asynchronous/event oriented programming.

What if you were to change jobs to a company that uses ExtJs instead of jQuery? Understanding the core concepts of the language will make these sorts of transitions non-problematic.

Another thing to consider is that for every library, there is always a task that it doesn't support. Being reliant on a library to always do the heavy lifting will eventually bite you in the hind parts.

Does coding in plain JavaScript increase performance compared to coding with jQuery?

Libraries typically aim to be as generic as possible for the area of use they are targeting. Because of this, inefficiencies may occur in some scenarios that could be otherwise optimized outside of the library.

It all depends on how adept you are at JavaScript, algorithm selection/creation/analysis, and programming in general. When you start concerning yourself with being as high performing as possible, you really need to be able to get down to the finer details of a language. "Being good" at jQuery, or any library for that matter, will likely not help you with this (unless you're looking under the hood and implementing their techniques in a manner that is specific to your scenario).

jQuery is just a list of (very) useful functions, written in JavaScript.

You are just using the library without understanding what's behind it and how things work. Most of the time you will only need jQuery for maybe 20%-40% of your code, and the rest will be pure JavaScript, so I encourage you to learn the basics. These are good places to start with:

• http://www.w3schools.com/jsref

• http://howtonode.org/what-is-this

• http://net.tutsplus.com/tutorials/javascript-ajax/the-basics-of-object-oriented-javascript/

• http://ejohn.org/apps/learn/

I'm a bit ambiguous on this. Knowing real deep JavaScript is a great art - I am always in awed silence when one of our resident deep JavaScript experts comes to the table. However, not everyone needs that kind of deep knowledge - if you're focused on building interfaces, knowing one of the frameworks well may be everything you ever need, with very few edge cases.

On the other hand, knowing at least the basics of how JavaScript works under the hood can only be beneficial. If you feel driven to take a look into it, I'd say do it. You don't have to become a total guru in fundamental JavaScript but having a basic idea of how data is handled internally, how events are processed by the browser, how memory is managed, etc. is a good thing.

Not necessarily, it is like saying like being good in Java is same being good in byte code since it is using the byte code.

jQuery is an abstraction layer for JavaScript, and for this reason most of the time you will be doing it all in jQuery rather than raw JavaScript. However, it is always a good idea to have some JavaScript knowledge at least for the required parts.

For this reason, if you see any jQuery book out there, most of them have a chapter or index regarding the "Basics Of JavaScript" or "JavaScript for jQuery".