function DynamicOptionList() {
  if (arguments.length < 2) { alert("Not enough arguments in DynamicOptionList()"); }
  this.target = arguments[0];
  this.dependencies = new Array();
  for (var i=1; i<arguments.length; i++) {
    this.dependencies[this.dependencies.length] = arguments[i];
  }
  this.form = null;
  this.dependentValues = new Object();
  this.defaultValues = new Object();
  this.options = new Object();
  this.delimiter = "|";
  this.longestString = "";
  this.numberOfOptions = 0;
  this.ao = DynamicOptionList_addOptions;
  this.populate = DynamicOptionList_populate;
  this.setDelimiter = DynamicOptionList_setDelimiter;
  this.setDefaultOption = DynamicOptionList_setDefaultOption;
  this.printOptions = DynamicOptionList_printOptions;
  this.init = DynamicOptionList_init;
}

function DynamicOptionList_setDelimiter(val) {
  this.delimiter = val;
}

function DynamicOptionList_setDefaultOption(condition, val) {
  this.defaultValues[condition] = val;
}

function DynamicOptionList_init(theform) {
  this.form = theform;
  this.populate();
}

function DynamicOptionList_addOptions(dependentValue) {
  if (typeof this.options[dependentValue] != "object") { this.options[dependentValue] = new Array(); }
  for (var i=1; i<arguments.length; i+=2) {
    if (arguments[i].length > this.longestString.length) {
      this.longestString = arguments[i];
    }
    this.numberOfOptions++;
    this.options[dependentValue][this.options[dependentValue].length] = arguments[i];
    this.options[dependentValue][this.options[dependentValue].length] = arguments[i+1];
  }
}

function DynamicOptionList_printOptions() {
  if ((navigator.appName == 'Netscape') && (parseInt(navigator.appVersion) <= 4) || (navigator.appName == 'Opera')) {
    var ret = "";
    for (var i=0; i<this.longestString.length/2; i++) { 
      ret += "_";
      }
    document.writeln(ret+"</option>");
    }
  }

function DynamicOptionList_populate() {
  var theform = this.form;
  var i,j,obj,obj2;
  this.dependentValues = new Object;
  var dependentValuesInitialized = false;
  for (i=0; i<this.dependencies.length;i++) {
    var sel = theform[this.dependencies[i]];
    var selName = sel.name;
    if (!dependentValuesInitialized) {
      dependentValuesInitialized = true;
      for (j=0; j<sel.options.length; j++) {
        if (sel.options[j].selected) {
          this.dependentValues[sel.options[j].value] = true;
        }
      }
    } else {
      var tmpList = new Object();
      var newList = new Object();
      for (j=0; j<sel.options.length; j++) {
        if (sel.options[j].selected) {
          tmpList[sel.options[j].value] = true;
        }
      }
      for (obj in this.dependentValues) {
        for (obj2 in tmpList) {
          newList[obj + this.delimiter + obj2] = true;
        }
      }
      this.dependentValues = newList;
    }
  }
  var targetSel = theform[this.target];
  var targetSelected = new Object();
  for (i=0; i<targetSel.options.length; i++) {
    if (targetSel.options[i].selected) {
      targetSelected[targetSel.options[i].value] = true;
    }
  }

  targetSel.options.length = 0; // Clear all target options
  targetSel.options[0] = new Option("-------------------------------","0",false,false);
  for (i in this.dependentValues) {
    if (typeof this.options[i] == "object") {
      var o = this.options[i];
      for (j=0; j<o.length; j+=2) {
        var text = o[j];
        var val = o[j+1];
        targetSel.options[targetSel.options.length] = new Option(text, val, false, false);
        if (this.defaultValues[i] == val) {
          targetSelected[val] = true;
        }
      }
    }
  }
}