D3和 jQuery 有什么区别？

d3 has a silly description. jQuery and d3 are not at all similar, you just don't use them for the same things.

jQuery's purpose is to do general dom manipulation. It's a general purpose javascript toolkit for anything you might want to do.

d3 was primarily designed to make it easy to make shiny graphs with data. You should definitely use it (or something similar, or something built on top of it) if you want to make graphical visualizations of data.

If you want a general purpose JS library for all your interactive form needs, consider jQuery or proto or mootools. If you want something tiny, consider underscore.js. If you want something with dependency injection and testability, consider AngularJS.

A General comparison guide from wikipedia.

I can see why someone would think they are similar. They use a similar selector syntax -- $('SELECTOR'), and d3 is an extremely powerful tool for selecting, filtering, and operating on html elements, especially while chaining these operations together. d3 tries to explain this to you on its home page by claiming to be a general purpose library, but the fact is that most people use it when they want to make graphs. It is pretty unusual to use it for your average dom manipulation because the d3 learning curve is so steep. It is, however, a far more general tool than jQuery, and generally people build other more specific libraries (such as nvd3) on top of d3 rather than using it directly.

@JohnS's answer is also very good. Fluent API = method chaining. I also agree about where the plugins and extension lead you with the libraries.

d3 is made for data visualization, it does this by filtering through DOM objects and applying transformations.

jQuery is made for DOM manipulation and making life easier for many basic JS tasks.

If you're looking to turn data into pretty, interactive pictures, D3 is awesome.

If you're looking to move, manipulate or otherwise modify your webpage, jQuery is your tool.

• D3 is data-driven but jQuery is not: with jQuery you directly manipulate elements, but with D3 you provide data and callbacks through D3's unique data(), enter() and exit() methods and D3 manipulates elements.

• D3 is usually used for data visualization but jQuery is used for creating web apps. D3 has many data visualization extensions and jQuery has many web app plugins.

• Both are JavaScript DOM manipulation libraries, have CSS selectors and fluent API and are based on web standards which makes them look similar.

Following code is an example of D3 usage which is not possible with jQuery (try it in jsfiddle):

  // create selection
var selection = d3.select('body').selectAll('div');


// create binding between selection and data
var binding = selection.data([50, 100, 150]);


// update existing nodes
binding
.style('width', function(d) { return d + 'px'; });


// create nodes for new data
binding.enter()
.append('div')
.style('width', function(d) { return d + 'px'; });


// remove nodes for discarded data
binding.exit()
.remove();

I've been using a little of both lately. Since d3 uses Sizzle's selectors you can pretty much mix up selectors.

Just keep in mind d3.select('#mydiv') doesn't return quite the same as jQuery('#mydiv'). It's the same DOM element, but it's being instantiated with different constructors. For example, let's say you have the following element:

<div id="mydiv" rel="awesome div" data-hash="654687867asaj"/>

And let's grab some common methods:

> d3.select('#mydiv').attr('rel') ;
"awesome div"


> jQuery('#mydiv').attr('rel');
"awesome div"

Seems legit. But if you go a little further:

> d3.select('#mydiv').data();
[undefined]


> jQuery('#mydiv').data();
Object {hash: "654687867asaj"}

Great question!

While both libraries share many of the same features, it seems to me that the greatest difference between jQuery and D3 is the focus.

jQuery is a general purpose library with a focus on being cross-browser and being easy to use.

D3 is focused on data (manipulation and visualisation) and supports only modern browsers. And while it does look like jQuery, it's a lot more difficult to use.

D3 is not just about visual graphs. Data Driven Documents. When you use d3, you bind data to dom nodes. Because of SVG we are able to make graphs, but D3 is so much more. You can replace frameworks like Backbone, Angular, and Ember with using D3.

Not sure who down voted, but let me add some more clarity.

Many websites request data from the server, which usually comes from a database. When the website receives this data, we have to do a page update of the new content. Many frameworks do this, and d3 does this as well. So instead of using a svg element, you can use html element instead. When you call the redraw, it'll quickly update the page with the new content. It's real nice to not have all the extra overhead like jquery, backbone + its plugins, angular, etc. You only need to know d3. Now d3 doesn't have a routing system baked into it. But you can always find one.

Jquery on the other hand, it's sole purpose is to write less code. It's just a short hand version of javascript that has been tested on many browsers. If you don't have a lot of jquery on your webpage. It's a great library to use. It's simple and takes a lotta pains out of javascript development for multiple browsers.

If you tried to implement jquery in a d3 like fashion, it'll be quite slow, as it wasn't designed for that task, likewise, d3 isn't design to post data to servers, it's designed just to consume and render data.

Both can solve the same purpose of creating and manipulating a DOM (whether it be HTML or SVG). D3 surfaces an API that simplifies common tasks you would take when generating/manipulating a DOM based on data. It does this through it's native support for data binding via the data() function. In jQuery you would have to manually process the data and define how to bind to the data in order to generate a DOM. Because of this, your code becomes more procedural and harder to reason and follow. With D3, it's less steps/code and more declarative. D3 also provides some higher level functions that aid in generating data visualization in SVG. Functions like range(),domain(), and scale() make it easier to take data and plot them on a graph. Functions like axis() also make it easier to draw common UI elements you would expect in a chart/graph. There are many other higher-level api libraries that sit on top of D3 to aid in more complex visualizations of data including interactive behavior and animation.