Aptana Studio supports syntax highlighting for the array of languages  mentioned above. This helps root out elementary errors such as typos. In addition to syntax highlighting, Aptana Studio supports a code assist feature for HTML, CSS and Javascript. What this does is it visually shows your what elements are compatible with whichever web browsers you are targeting.   There is support for internal Javascript debugging with integration to Firefox and Internet Explorer. Not only does Aptana Studio provides debugging for Javascript. It also provides libraries for several Javascript and Ajax Frameworks such as JQuery, Sencha formerly known as Ext JS, Prototype, Scriptaculous and others which help to increase productivity of your projects.

Bluefish is a powerful editor targeted towards programmers and webdesigners, with many options to write websites, scripts and programming code. Bluefish supports many programming and markup languages, and it focuses on editing dynamic and interactive websites. This editor is very handy and can save you a lot of time. One of the best features is the extensive autosuggestion of HTML, PHP, CSS and other scripting languages. Also the syntaxis is displayed very well so you can see how the code works.

IETester is a free WebBrowser that allows you to have the rendering and javascript engines of IE9, IE8, IE7 IE 6 and IE5.5 on Vista and XP, as well as the installed IE in the same process. This is very handy for webdeveloppers to test websites in Internet Explorer.