There are very many pay and free editors for work with PHP, HTML, CSS, and JavaScript.
I would like to particularly note easy and free and, at the same time, very powerful and convenient editor Codelobster PHP Edition.

Below there is a brief review of its functionalities:

While developing a web project, developers work with HTML pages most of all. Codelobster PHP Edition has a set of features which make developers’ work more convenient: Code highlighting depending on word type; Pair highlighting for a current tag; Intelligent Auto-complete for tags, attributes and their values. Context and Dynamic help works for all languages including HTML5 and CSS3. Press F1 opens a corresponding page of the documentation from the official site. There is also an ability to collapse written code, upon this a corresponding end tag is set automatically that is very convenient while working with tables.

Codelobster has a very friendly tooltip system. When the cursor is over an image, the system displays its thumbnail including additional information such as image’s size and volume. It displays color when the cursor is over any color, a style code when the cursor is over any code and special symbols as well. It is important to note that there is an ability to navigate while holding pressed CTRL. It is possible to navigate through all the images, attached files and, what is the most convenient, class names from .css files. That is if you click class=”class1” holding pressed CTRL, a corresponding CSS file with description of current selector will be opened. In order to insert tags there is a powerful enough HTML toolbar.

The very important advantage of this software product is HTML/CSS code inspector similar to FireBug or Chrome Developer Tools. Style changes are performed in a real physical file not in a virtual one at that.
It is also possible to use auto complete, tooltips and others in the window of styles. With the help of the code inspector you can easily associate any visual element with its code in file, the navigation is automatic.

Codelobster PHP Edition has an in-house developed debugger which includes all necessary to fully debug PHP code: an ability to set Breakpoints, execute scripts line-by-line, run or skip functions, and besides control values of variables and locals while debugging.

While working with PHP projects, Codelobster PHP Edition displays all variables and class functions described in a project or other files in the auto complete list.

There is a special embedded SQL manager for work with MySQL databases. It allows developers to execute all necessary operations with data: to view, add, delete, and edit. There is also an ability to edit tables (fields) structure. Codelobster PHP Edition provides a special wizard for data export. While working with SQL files highlighting and auto complete are activated automatically. Besides the keywords, auto complete feature displays all tables and their fields for a current database.

The rest useful features are the following: FTP/SFTP support, Portable option, Project manager, Bookmarks, TODO panel, Incremental find, Pair selection commands, comments etc.

In my opinion, nowadays this is one of the best PHP IDEs which has all necessary functionalities for web site development. At the same time its main advantages are easiness and quickness, HTML/CSS code inspector and SQL manager as well.

I would like to turn your attention again to Codelobster PHP Edition which is absolutely free including all mentioned features. Professional version is available for developers who use different frameworks. It supports Drupal CMS, Joomla CMS, Smarty Template Engine, WordPress blogging platform, CodeIgniter framework, CakePHP framework, Symfony framework, JQuery JavaScript Library, and Facebook Social Network.