/**
 *	Turns hidden form field on/off and changes image
 */
var imgSrcCheckBoxOn = "img/checkbox_on.gif";
var imgSrcCheckBoxOff = "img/checkbox_off.gif";
function checkBoxClick(image, formField, newValue) {
	if (formField.value) {
		formField.value = '';
		image.src = imgSrcCheckBoxOff;
	} else {
		if (newValue) {
			formField.value = newValue;
		} else {
			formField.value = '1';
		}
		image.src = imgSrcCheckBoxOn;
	}
}