createTheProperSubClass.js

<!--
function createTheProperSubClass() {
  var browserType = new browserSniffer();
  if (browserType.ie4) {
    this.className = "docjslibIE4SubClass";
  }
  else if (browserType.ie5) {
    this.className = "docjslibIE5SubClass";
  }
  else if (browserType.ns4) {
    this.className = "docjslibNS4SubClass";
  }
  else if (browserType.ns6) {
    this.className = "docjslibNS6SubClass";
  }
  
  this.getTheProperSubClass = getTheProperSubClassMethod;
  
  function getTheProperSubClassMethod() {
    // example: return new docjslibIE5SubClass();
	return eval('new ' + this.className + '()');
  }
}
// -->

Next: Browser-independent superclass