//
//	Returns true if all of the non-optional fields in the given
//	form have been assigned values.  If a value is missing, a
//	non-null error message is returned.  If a label attribute
//	is defined for that field, then it will be used in the
//	error message.  For example, the following code segment
//	validates a form with two required fields and one optional field:
//
//		form.field1.label    = "Field 1";
//		form.field2.label    = "Field 2";
//		form.field3.optional = true;
//
//		var err = validateForm(form);
//		if (err) alert(err);
//
function validateForm (form)
{

// Check for all required (non-optional), non-hidden field values

	for (i=0; i<form.length; i++) {
		var e = form.elements[i];
		var label = e.label ? e.label : e.name;

		if (isBlank(e.name) || e.optional)
			continue;

		if (e.type == "hidden")
			continue;

		if (e.type == "select-one" || e.type == "select-multiple") {
			if (e.selectedIndex == -1)
				return "Please Select A Value From The "
						+label+" Field.";
			continue;
		}

		if (isBlank(e.value))
			return "Please Enter A Value Into The "
					+label+" Field.";
	}

	return null;
}

//
//	Validates the given form and submits it with the given action URL
//	if succesful.  If a validation error occurs, an alert window
//	is displayed.
//
function validateAndSubmit (form, url)
{
	var err = validateForm(form);
	if (err) {
		alert (err);
		return;
	}
	submitForm (form, url);
}


//
//	Validate the given form, and alert if there is an error
//	If there was an error, return it. Otherwise return null
//
function validateAndAlert (form)
{
	var err = validateForm(form);
	if (err) {
		alert (err);
		return err;
	}
	else
		return null;
}


//
//	Submits the given form using the given action URL.
//
function submitForm (form, url)
{
	form.action = url;
	form.submit();
}

//
//
//	Clears the given form after confirming that operation with the user
//
function resetForm (form)
{
	var ok = confirm (
			"All values currently entered into the form\n"
			+"will be reset to their original values.\n"
			+"\n"
			+"Do you still want to proceed?");

	if (ok) {
		form.reset();
		formResetCheckBoxes (form);
	}
}

//
//	Returns true if the given string is null or contains only whitespace
//
function isBlank (s)
{
	if (s == null)
		return true;

	for (var i=0; i<s.length; i++) {
		var c = s.charAt(i);
		if ((c != ' ') && (c != '\n') && (c != '\t'))
			return false;
	}

	return true;
}

var formCheckBoxOffImage = "/skipjack/images/checkbox/box-empty-16.gif";
var formCheckBoxOnImage = "/skipjack/images/checkbox/box-black-x-16.gif";

//
//	Toggles the value and image of the given image checkbox
//
function formToggleCheckBox (form, hiddenField, imageField)
{
	var fld = form[hiddenField];
	var img = form[imageField];

	for (i=0; i<formCheckBoxList.length; i++) {
		if (fld.name == formCheckBoxList[i].name) {
			if (fld.value == "on") {
				formSetCheckBox (fld, img, i, "off");
			} else {
				formSetCheckBox (fld, img, i, "on");
			}
			break;
		}
	}

	window.status = "";
}

var formFocusField = null;
var formCheckBoxList = new Array();
var formCheckBoxDflt = new Array();
var formCheckBoxOnImage = new Array();
var formCheckBoxOffImage = new Array();

//
//	This function should be called whenever a form page is loaded.
//	It sets all checkbox images to the proper image and sets the
//	focus field (if defined).
//
function formPageLoad ()
{
	for (i=0; i<formCheckBoxList.length; i++) {
		fld = formCheckBoxList[i];
		form = fld.form;
		img = form[fld.name+'CheckBox'];
		formSetCheckBox (fld, img, i, fld.value);
	}	

	if (formFocusField != null) {
		formFocusField.focus();
		formFocusField.select();
	}
}

//
//	Resets the each checkbox field defined for the given form
//	to its originally defined value
//
function formResetCheckBoxes (form)
{
	for (i=0; i<formCheckBoxList.length; i++) {
		fld = formCheckBoxList[i];
		if (fld.form.name == form.name) {
			img = form[fld.name+'CheckBox'];
			formSetCheckBox (fld, img, i, formCheckBoxDflt[i]);
		}
	}
}

//
//	Sets the image source for the given checkbox image field based on
//	the current value of the given checkbox hidden field
//
function formSetCheckBox (fld, img, i, value)
{
	fld.value = value;

	if (fld.value == "on") {
		if (img.src != formCheckBoxOnImage[i]) {
			img.src = formCheckBoxOnImage[i];
		}
	} else {
		if (img.src != formCheckBoxOffImage[i]) {
			img.src = formCheckBoxOffImage[i];
		}
	}
}

//
//	Returns the current value for the set of radio choices with
//	the given name.  If no value is currently selected, null]
//	is returned.
//
function formGetRadioValue (form, fldName)
{
	for (i=0; i<form.length; i++) {
		var e = form.elements[i];
		if (e.name == null || e.name != fldName || e.type != "radio")
			continue;

		if (e.checked)
			return e.value;
	}

	return null;
}

//
//	Pops-up a HTML window.
//	
//	"url" may be a Url to be displayed in the window, or an empty
//	string.  If "url" is an empty string, the string in the "text"
//	argument will be displayed in the window.
//
//	"name" uniquely names this window.  If another window with the
//	same name is already being displayed, it will be used.
//
//	"text" will be written to the window if "url" is an empty string.
//
//	"width" and "height" define the dimensions of the window.
//
//	"scroll" causes scrollbars to be displayed as needed when set to "yes".
//	scrollbars are omitted if set to "no".
//
//	"pos" may be set to one of: "center" or "default".  If set to "center",
//	the window will be centered on the screen.  If set to "default", it
//	will be displayed 50 pixels from the upper-left corner of the screen.
//
function popupWindow(url, name, text, title, width, height, scroll, pos)
{
	if (pos == "center") {
		LeftPosition=(screen.availWidth)?(screen.availWidth - width)/2 : 50;
		TopPosition=(screen.availHeight)?(screen.availHeight - height)/2 : 50;
	}
	else if (pos == "default") {
		LeftPosition=50;TopPosition=50
	}
	settings='width='+width+',height='+height+',top='+TopPosition+',left='+LeftPosition+',scrollbars='+scroll+',location=no,directories=no,status=no,menubar=no,toolbar=no,resizable=no';
	win=window.open(url,name,settings);
	win.document.open();
	win.document.write("<html><head><title>");
	win.document.write(title);
	win.document.write('</title></head><body bgcolor="gainsboro"><span class=helpText>');
	win.document.write(text);
	win.document.write("</span></body></html>");
	if (win.focus) {
		win.focus();
	}
}