// A utility to confirm whether you want to delete an item or not
function confirmDelete() {
	return confirm("Are you sure you want to DELETE this item?");
}

// A utility function returns true if a string contains
// only whitespace characters
function isblank(s) {
	for(var i=0; i < s.length; i++) {
		var c = s.charAt(i);
		if ((c != ' ') && (c != '\n') && (c != '')) return false;
	}
	return true;
}

//This is the function that performs form verification.  It is invoked
// from the onsubmit event handler.  The handler should return whatever
// value this function returns.
function verify(f) {
	var msg;
	var empty_fields = "";
	var errors = "";
	
	// Loop through the elements of the form, looking for all of the Text and
	// Textarea elements that don't have an "optional" property defined.
	// Then check for fields that are empty and make a list of them.  Also, if
	// any of these elements have a "min" or a "max" property defined, verify 
	// that they are numbers and are in the right range.  If the element has a 
	// "numeric" property defined, verify that it is a number, but don't check
	// its range.  Put together error messages for fields that are wrong.
	for(var i = 0; i < f.length; i++) {
		var e = f.elements[i];
		if (((e.type == "text") || (e.type == "textarea")) && !e.optional) {
			// First check if the field is empty
			if ((e.value == null) || (e.value == "") || isblank(e.value)) {
				empty_fields += "\n        " + e.name;
				continue;
			}
			
			// Now check for fields that are supposed to be numeric
			if (e.numeric || (e.min != null) || (e.max != null)) {
				var v = parseFloat(e.value);
				if (isNaN(v) ||
					((e.min != null) && (v < e.min)) ||
					((e.max != null) && (v > e.max))) {
					errors += "- The field " + e.name + " must be a number";
					if (e.min != null)
						erros += " that is greater than " + e.min;
					if (e.max != null && e.min != null)
						errors += " and less than " + e.max;
					else if (e.max != null)
						errors += " that is less than " + e.max;
					errors += ".\n";
				}
			}
		}
	}
	
	// Now, if there were any errors, display the messages, and 
	// return false to prevent the form from being submitted.
	// Otherwise, return true.
	if (!empty_fields && !errors) return true;
	
	msg = "__________________________________________________\n\n"
	msg += "The form was NOT submitted because of the following error(s). \n";
	msg += "Please corrent these error(s) and re-submit.\n";
	msg += "__________________________________________________\n\n"
	
	if (empty_fields) {
		msg += "- The following required field(s) are empty:"
			+ empty_fields + "\n";
		if (errors) msg += "\n";
	}
	msg += errors;
	alert(msg);
	return false;
}