Re-size your browser window. If the browser is handling SVG graphics properly, the graphics should scale accordingly.
This uses simple web standards, HTML, CSS, and SVG. No scripting is involved.
Several things need to be in place for it to work.
In the SVG graphics file, the outermost
viewBox attribute to define its internal
coordinate ranges, but its
attributes must be given as percentages.
In the HTML file, the CSS for the containing HTML elements needs to be set up to properly scale with the window size.