FoxReplace allows you to replace text fragments in a page by other text fragments. The system is based in substitutions: a substitution consists in a text which has to be replaced (identified as "Replace") and a text by which the first has to be replaced (identified as "With"). All substitutions are always applied over the whole content of a page (you can't do partial substitutions at the moment). Substitutions can be case-sensitive or insensitive. The use of regular expressions is also supported.
You can have predefined substitutions in a substitution list to apply them all at once, and also do individual substitutions. You also have the option to apply the substitution list automatically whenever a page is loaded.