A good JavaScript (wikipedia) Source Code Editor will help to greatly enhance the efficiency of developers.

According to our investigation, most developers are now using a general editor / IDE to edit JavaScript, thus they can rely on just one tool to handle development in all languages, including HTML, PHP, CSS, JavaScript etc.

5 specialized JavaScript toolsAlso, there are many specialized JavaScript development tools in the market. We have searched a lot and found the following 5 specialized JavaScript tools that come with distinctive features and good user experience.

Product	Price	Excerpt
WebStrom	$49 - $99	The smartest JavaScript IDE
JSDT	Free	JavaScript IDE for Eclipse based on the Java development tools
JSFIDDLE	Free	- The best free online JavaScript editor - Provides separate sections for html, css, and javascript
Online Javascript Editor	Free	- Clear UI - Supports JavaScript only
JS.do	Free	- Clear UI - Supports JavaScript only
JS Bin	Free You can pay £60/ Year + VAT to get more features	- Online editor - Collaborative JavaScript debugging

You can refer to these 2 articles for more JavaScript editors and reviews
Review: 10 JavaScript editors and IDEs put to the test
Comparison of JavaScript-based source code editors

TipsThere are many splendid JavaScript plugins and platforms available

For example, the following two are excellent JavaScript platforms:
Note.js
Jquery

Nowadays, you can download from the Internet or purchase various pre-made JavaScript effects, saving yourself the trouble of developing them.
JavaScript Kit (Free)
JavaScriptSource (Free)
CodeCanyon

Our editors have done the following work to save your time

List all the popular JavaScript source code editors.
Re-rank the products by brands reputation, product downloads, and product sales.
List the available discount coupons/deals for you, so that you can enjoy discount directly instead of the time-consuming searching for a coupon.