This parser strips down all potentially dangerous content within HTML:
* opening tag without its closing tag
* closing tag without its opening tag
* any of these tags: "base", "basefont", "head", "html", "body", "applet",
"object", "iframe", "frame", "frameset", "script", "layer", "ilayer",
"embed", "bgsound", "link", "meta", "style", "title", "blink", "xml", etc.
* any of these attributes: on*, data*, dynsrc
* javascript:/vbscript:/about: etc. protocols
* expression/behavior etc. in styles
* any other active content
It also tries to convert code to XHTML valid, but htmltidy is far better solution for this task.