Check IE version

check_ie_version.js

// source from: http://stackoverflow.com/questions/5940845/how-detect-ie6-with-javascript/5940884#5940884

function getInternetExplorerVersion() {
// Returns the version of Internet Explorer or a -1
// (indicating the use of another browser).
  var rv = -1; // Return value assumes failure.
  if (navigator.appName == 'Microsoft Internet Explorer') {
    var ua = navigator.userAgent;
    var re  = new RegExp("MSIE ([0-9]{1,}[\.0-9]{0,})");
    if (re.exec(ua) != null)
      rv = parseFloat( RegExp.$1 );
  }
  return rv;
}

//And if you're a minimalist, a bit of a rebel; this method I believe actually works:
//if (typeof document.body.style.maxHeight != "undefined") {
    // IE 7, moz, saf, opera 9
//    } else {
    // IE6, older browsers
//}