Inkscape is purely an SVG editor, yes you can also view SVG images using inkscape but that is not its primary function. MathJaX’s primary function on the other hand is to find mathexpressions on a web page and then use javascript to turn them into HTML+CSS rendered equation.
If you want to write LaTeX and include the equivalent MathML in your webpage, then something like Temml is a lot better choice, as that is it’s primary function.
I'd say the opposite: now we can safely use MathJAX to translate TeX syntax to an efficient rendering representation.