function switchCheckbox(srcImg){
	var fieldName = srcImg.id + '_field';
	var hiddenField = document.getElementById(fieldName);
	srcImg.src = srcImg.src.indexOf('_unchecked') != -1 ? srcImg.src.replace(/_unchecked/, "_checked") : srcImg.src.replace(/_checked/, "_unchecked") ;
	hiddenField.value = hiddenField.value == 'true' ? 'false' : 'true' ;
}