init();
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.srcElement.style.backgroundPosition == '-250px 0px')
{
 //already clicked  	  
}
else
{

if(evt.srcElement.disabled) return

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";
}

}