var regCSS = "style.css";
var macNSCSS = "style_ns.css";
var navImgDir = "images/";
var onImg = new Array();
var offImg = new Array();

// convert all characters to lowercase to simplify testing 
var agt=navigator.userAgent.toLowerCase(); 

// *** BROWSER VERSION *** 
var is_major = parseInt(navigator.appVersion); 
var is_minor = parseFloat(navigator.appVersion); 

// *** BROWSER TYPE *** 
var is_nav  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1) 
            && (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1) 
            && (agt.indexOf('webtv')==-1));
var is_nav4up = (is_nav && (is_major >= 4));  
var is_ie   = (agt.indexOf("msie") != -1); 
var is_ie3  = (is_ie && (is_major < 4)); 
var is_ie4  = (is_ie && (is_major == 4) && (agt.indexOf("msie 5.0")==-1) );
var is_ie4up  = (is_ie  && (is_major >= 4));
var is_ie5  = (is_ie && (is_major == 4) && (agt.indexOf("msie 5.0")!=-1) );  
var is_ie5up  = (is_ie  && !is_ie3 && !is_ie4);  

// *** PLATFORM ***
var is_mac    = (agt.indexOf("mac")!=-1);
	 
//  Select the appropriate stylesheet
if ((is_nav4up || is_ie4up) || (!is_nav && !is_ie)) {
  ChooseStyleSheet();
}

// Function to choose the style sheet for use based on the platform
// and browser version
function ChooseStyleSheet() {
  var styles;
  if (is_mac) {
	if (is_nav) {
      styles = macNSCSS;
	} else {
	  // Default style = regCSS
	  styles = regCSS;
	}
  } else {
    // Default style = regCSS
	styles = regCSS;
  }
  document.write("<link rel=\"stylesheet\" type=\"text/css\" href=\"" + styles + "\">");
  return true;
}

// For top nav roll overs
var topNavNames = new Array("","");
var imgName, imgHLName, refName;
if (document.images) {
  for (var i = 0; i < topNavNames.length; i++) {
    refName = topNavNames[i];
    imgName = navImgDir + refName + "_off.jpg";
	imgHLName = navImgDir + refName + "_on.jpg";
	onImg[refName] = new Image();
	offImg[refName] = new Image();
	onImg[refName].src = imgHLName;
	offImg[refName].src = imgName;
  }
}

// Swap images on based on a name array
function imageOn(name) {
   if (document.images) {
    document.images[name].src = onImg[name].src
   }
}

// Swap images off based on a name array 
function imageOff(name) {
   if (document.images) {
    document.images[name].src = offImg[name].src
   }
}