function init() {
  var jsImgButton;
  jsImgButton = document.getElementsByName("jsimgbutton");
  for(var i=0; i < jsImgButton.length; i++) {
    jsImgButton[i].onmouseover = jsImgButton[i].onmouseup = jsImgButton[i].onmouseout = jsImgButton[i].onmousedown = ButtonState;
  }
}

function ButtonState(evt) {
  if( !evt)
    evt = event;
  else
    evt.srcElement = evt.target;

  var btnWidth = parseInt(evt.srcElement.style.width);

  if(evt.type == "mouseover" )
    evt.srcElement.style.backgroundPosition = "-" + btnWidth+ "px 0px";
  if(evt.type == "mouseout" )
    evt.srcElement.style.backgroundPosition = "0px 0px";
  if(evt.type == "mousedown" )
    evt.srcElement.style.backgroundPosition = "-" + btnWidth * 2 + "px 0px";
  if(evt.type == "mouseup" )
    evt.srcElement.style.backgroundPosition = "-" + btnWidth+ "px 0px";
}

// Multiple onload function created by: Simon Willison
// http://simon.incutio.com/archive/2004/05/26/addLoadEvent
function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

addLoadEvent(function() {
  init();
});