Detecting the browser using simple javascript function

Where the code used to check for if (ie) { ... }, now I wanted it to check for if (ie6OrLower) { ... }. So how to you tell the difference between IE 6 and IE 7+? You could parse the user-agent string, but I’d rather detect changes in the javascript object model. Here’s what I came up with:

if (typeof document.body.style.maxHeight != "undefined") {
  // IE 7, mozilla, safari, opera 9
} else {
  // IE6, older browsers
}

This distinguishes between browsers based on the fact that IE 7 knows about the maxHeight css property, whereas previous versions of IE didn’t.