2固定导航栏全浏览器宽度和高度

I want to position:fix a navigation to the left side of the browser window (100% height). Then on the right side I want to fix a subnav to the top of the browser window (100% width) so that as the page scrolls, both navs stick. And if the window is resized, the bars always run 100%. I want to position:fix a navigation to the left