function CheckBoxGroup() {
	this.controlBox = null;
	this.controlBoxChecked = null;
	this.maxAllowed = null;
	this.maxAllowedMessage = null;
	this.masterBehavior = null;
	this.formRef = null;
	this.checkboxWildcardNames = new Array();
	this.checkboxNames = new Array();
	this.totalBoxes = 0;
	this.totalSelected = 0;
	// Public methods
	this.setControlBox = CBG_setControlBox;
	this.setMaxAllowed = CBG_setMaxAllowed;
	this.setMasterBehavior = CBG_setMasterBehavior; // all, some
	this.addToGroup = CBG_addToGroup;
	// Private methods
	this.expandWildcards = CBG_expandWildcards;
	this.addWildcardCheckboxes = CBG_addWildcardCheckboxes;
	this.addArrayCheckboxes = CBG_addArrayCheckboxes;
	this.addSingleCheckbox = CBG_addSingleCheckbox;
	this.check = CBG_check;
}

// Set the master control checkbox name
function CBG_setControlBox(name) {
	this.controlBox = name;
}

// Set the maximum number of checked boxes in the set, and optionally
// the message to popup when the max is reached.
function CBG_setMaxAllowed(num, msg) {
	this.maxAllowed = num;
	if (msg != null && msg != "") {
		this.maxAllowedMessage = msg;
	}
}

// Set the behavior for the checkbox group master checkbox
// All: all boxes must be checked for the master to be checked
// Some: one or more of the boxes can be checked for the master to be checked
function CBG_setMasterBehavior(b) {
	this.masterBehavior = b.toLowerCase();
}

// Add checkbox wildcards to the checkboxes array
function CBG_addToGroup() {
	if (arguments.length > 0) {
		for ( var i = 0; i < arguments.length; i++) {
			this.checkboxWildcardNames[this.checkboxWildcardNames.length] = arguments[i];
		}
	}
}

// Expand the wildcard checkbox names given in the addToGroup method
function CBG_expandWildcards() {
	if (this.formRef == null) {
		alert("ERROR: No form element has been passed.  Cannot extract form name!");
		return false;
	}
	for ( var i = 0; i < this.checkboxWildcardNames.length; i++) {
		var n = this.checkboxWildcardNames[i];
		var el = this.formRef[n];
		if (n.indexOf("*") != -1) {
			this.addWildcardCheckboxes(n);
		} else if (CBG_nameIsArray(el)) {
			this.addArrayCheckboxes(n);
		} else {
			this.addSingleCheckbox(el);
		}
	}
}

// Add checkboxes to the group which match a pattern
function CBG_addWildcardCheckboxes(name) {
	var i = name.indexOf("*");
	if ((i == 0) || (i == name.length - 1)) {
		searchString = (i) ? name.substring(0, name.length - 1) : name
				.substring(1, name.length);
		for ( var j = 0; j < this.formRef.length; j++) {
			currentElement = this.formRef.elements[j];
			if (currentElement.type == 'checkbox') {
				currentElementName = currentElement.name;
				var partialName = (i) ? currentElementName.substring(0,
						searchString.length) : currentElementName.substring(
								currentElementName.length - searchString.length,
								currentElementName.length);
				if (partialName == searchString) {
					if (CBG_nameIsArray(currentElement))
						this.addArrayCheckboxes(currentElement);
					else
						this.addSingleCheckbox(currentElement);
				}
			}
		}
	}
}

// Add checkboxes to the group which all have the same name
function CBG_addArrayCheckboxes(name) {
	if ((CBG_nameIsArray(this.formRef[name]))
			&& (this.formRef[name].length > 0)) {
		for ( var i = 0; i < this.formRef[name].length; i++) {
			this.addSingleCheckbox(this.formRef[name][i]);
		}
	}
}

function CBG_addSingleCheckbox(obj) {
	if (obj != this.formRef[this.controlBox]) {
		this.checkboxNames[this.checkboxNames.length] = obj;
		this.totalBoxes++;
		if (obj.checked) {
			this.totalSelected++;
		}
	}
}

// Runs whenever a checkbox in the group is clicked
function CBG_check(obj) {
	var checked = obj.checked;
	if (this.formRef == null) {
		this.formRef = obj.form;
		this.expandWildcards();
		if (this.controlBox == null || obj.name != this.controlBox) {
			this.totalSelected += (checked) ? -1 : 1;
		}
	}
	if (this.controlBox != null && obj.name == this.controlBox) {
		if (this.masterBehavior == "all") {
			for (i = 0; i < this.checkboxNames.length; i++) {
				this.checkboxNames[i].checked = checked;
			}
			this.totalSelected = (checked) ? this.checkboxNames.length : 0;
		} else {
			if (!checked) {
				obj.checked = (this.totalSelected > 0) ? true : false;
				obj.blur();
			}
		}
	} else {
		if (this.masterBehavior == "all") {
			if (!checked) {
				this.formRef[this.controlBox].checked = false;
				this.totalSelected--;
			} else {
				this.totalSelected++;
			}
			if (this.controlBox != null) {
				this.formRef[this.controlBox].checked = (this.totalSelected == this.totalBoxes) ? true
						: false;
			}
		} else {
			if (!obj.checked) {
				this.totalSelected--;
			} else {
				this.totalSelected++;
			}
			if (this.controlBox != null) {
				this.formRef[this.controlBox].checked = (this.totalSelected > 0) ? true
						: false;
			}
			if (this.maxAllowed != null) {
				if (this.totalSelected > this.maxAllowed) {
					obj.checked = false;
					this.totalSelected--;
					if (this.maxAllowedMessage != null) {
						alert(this.maxAllowedMessage);
					}
					return false;
				}
			}
		}
	}
}

function CBG_nameIsArray(obj) {
	return ((typeof obj.type != "string") && (obj.length > 0)
			&& (obj[0] != null) && (obj[0].type == "checkbox"));
}