/**
 * Rollover
 */
function roll_on() {
  this.src = this.src.replace(/_off/,'_on');
}
function roll_off() {
	this.src = this.src.replace(/_on/,'_off');
}
function img_test() {
  for (i = 0; i < document.images.length; i++) {
	if (document.images[i].src.indexOf('_off.') > 0) {
	  document.images[i].onmouseover = roll_on;
	  document.images[i].onmouseout = roll_off;
	}
  }
}