function DynamicOptionList()
{
	if (arguments.length < 2) {
		alert("Not enough arguments in DynamicOptionList()");
	   	return false;
	}

	// Name of the list containing dynamic values
	this.target = arguments[0];

	// Set the lists that this dynamic list depends on
	this.dependencies = new Array();
	for (var i=1; i<arguments.length; i++) {
		this.dependencies[this.dependencies.length] = arguments[i];
		}

	// The form this list belongs to
	this.form = null;

	// Place-holder for currently-selected values of dependent select lists
	this.dependentValues = new Object();
	// Hold default values to be selected for conditions
	this.defaultValues = new Object();
	// Storage for the dynamic values
	this.options = new Object();
	// Delimiter between dependent values
	this.delimiter = "|";
	// Logest string currently a potential options (for Netscape)
	this.longestString = "";
	// The total number of options that might be displayed, to build dummy options (for Netscape)
	this.optionCount = 0;
	// Method mappings
	this.addOptions = DynamicOptionList_addOptions;
	this.populate = DynamicOptionList_populate;
	this.setDelimiter = DynamicOptionList_setDelimiter;
	this.setDefaultOption = DynamicOptionList_setDefaultOption;
	this.dumpOptions = DynamicOptionList_dumpOptions;
	this.printOptions = DynamicOptionList_printOptions;
	this.init = DynamicOptionList_init;
	this.getValue = DynamicOptionList_getValue;
}

// Set the delimiter to something other than | when defining condition values
function DynamicOptionList_setDelimiter(val)
{
	this.delimiter = val;
}

// Set the default option to be selected when the list is painted
function DynamicOptionList_setDefaultOption(condition, val)
{
	this.defaultValues[condition] = val;
}

// Init call to map the form to the object and populate it
function DynamicOptionList_init(theform)
{
	this.form = theform;
	this.populate();
}

// Add options to the list.
// Pass the condition string, then the list of text/value pairs that populate the list
function DynamicOptionList_addOptions(dependentValue)
{
	if (typeof this.options[dependentValue] != "object")
		this.options[dependentValue] = new Array();

	for (var i=1; i<arguments.length; i+=2) {
		// Keep track of the longest potential string, to draw the option list
		if (arguments[i].length > this.longestString.length) {
			this.longestString = arguments[i];
		}
		this.options[dependentValue][this.options[dependentValue].length] = arguments[i];
		this.options[dependentValue][this.options[dependentValue].length] = arguments[i+1];
		this.optionCount++;
	}
}

// Print dummy options so Netscape behaves nicely
function DynamicOptionList_printOptions()
{
	// Only need to write out "dummy" options for Netscape
    if ((navigator.appName == 'Netscape') && (parseInt(navigator.appVersion) <= 4))
    	this.dumpOptions();
}

function DynamicOptionList_dumpOptions()
{
    var ret = "";
    for (var i=0; i<this.optionCount; i++) {
        ret += "<option>";
    }
    ret += "<option>"
    for (var i=0; i<this.longestString.length; i++) {
        ret += "_";
    }
    document.writeln(ret);
}

// Populate the list
function DynamicOptionList_populate()
{
	var theform = this.form;
	if (!theform)
		return false;

	var i,j,obj,obj2;
	// Get the current value(s) of all select lists this list depends on
	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 this is the first dependent list, just fill in the dependentValues
		if (!dependentValuesInitialized) {
			dependentValuesInitialized = true;
			for (j=0; j<sel.options.length; j++) {
				if (sel.options[j].selected)
					this.dependentValues[sel.options[j].value] = true;
            }
        }

		// Otherwise, add new options for every existing option
		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];

	// Store the currently-selected values of the target list to maintain them (in case of multiple select lists)
	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

	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;
                }
            }
        }
    }
	targetSel.selectedIndex=0;
	targetSel.disabled = (targetSel.options.length==0);

	// Select the options that were selected before
	for (i=0; i<targetSel.options.length; i++) {
		if (targetSelected[targetSel.options[i].value] != null
				&& targetSelected[targetSel.options[i].value]==true) {
			targetSel.options[i].selected = true;
        }
    }
}

function DynamicOptionList_getValue()
{
	return this.target.value;
}

function DynamicOptionList_setValue( newValue )
{
	this.target.value = newValue;
}