The XML IDE ... modeling, editing, transforming, and debugging XML-related technologies, including an awesome graphical schema designer, code generation tools, file converters, debuggers, profilers, database integration, and explicit support for XSLT, XPath, XQuery, WSDL, SOAP, and Office Open XML (OOXML) documents. It even included Visual Studio and Eclipse plug-ins...
All of the tools you need to poke, prod, and monitor your JavaScript, CSS, HTML and Ajax are brought together into one seamless experience, including a debugger, error console, command line, and a variety of fun inspectors.
YouDebug is a Java program that lets you script a debug session through Groovy. You can think of it as a programmable, non-interactive debugger, you can create a breakpoint, evaluate expressions, have it dump threads, and a lot more, without requiring any source code. Your customer can just run the tool with the script you supplied, without any knowledge about Java.
Firebug is a phenomenally helpful HTML / CSS / JavaScript / Ajax debugger. Be that as it may, did you know it can likewise be utilized to troubleshoot PHP? Yes, on account of an additional Firefox extension called FirePHP.
A nice commecrial XML editor that not only has excellent validation, xslt and xpath and xquery, andformatting objects (fo) features, but supports an XML data grid view and XML Diff & Merge! It even supports generating SVG graphics via XSL transforms on data files, remote editing over FTP or WebDav, and is available as an Eclipse plugin. Only $48 for Academic use.