Checky is a document validation and analysis extension for Firefox, Mozilla, and Netscape. It provides an easy-to-use interface to many free and commercial online validation and analysis services. It allows the user to validate, analyze, view, and inspect documents containing HTML, XHTML, CSS, RDF, RSS, XML, P3P, hyperlinks, metadata, and many more. It can check Section 508 and WAI compliance of documents with many helpful services. It can help in the design, development, and maintenance of accessible documents for a semantic web.
ASCIIMathML is a script that converts calculator-style ASCII math notation (and many LaTeX formulas) to Presentation MathML while your Web page loads. It works with HTML and XHTML files in Mozilla/Firefox/Netscape 7+ browsers, as well as in Internet Explorer 6 with MathPlayer. For example, the solutions for the equation 'ax^2+bx+c=0' are expressed in the HTML file as '(-b +- sqrt(b^2 - 4ac))/(2a)', and display as nicely formatted MathML. The script can be easily used in wikiservers and blogs, as a rudimentary MathML editor (with instant preview), and to preview math formulas as they are typed into a Web page input area.