$(document).ready(
function() {
	var r =     Math.floor(Math.random()*2+1); // 1～2までのランダム数を得る 
$("#taisenkai_banner").css("background","url(./image/bg/taisenkai_bnrBG2_"+r+".jpg) 0 0 no-repeat");
$("#taisenkai_banner").css("cursor","pointer");

$("#taisenkai_banner").hover(
function(){
$(this).css("background","url(./image/bg/taisenkai_bnrBG2_"+r+".jpg) 0px -104px no-repeat");

},
function(){
$(this).css("background","url(./image/bg/taisenkai_bnrBG2_"+r+".jpg) 0px 0px no-repeat");

}
);
}
);