<script type='text/javascript'>
/* JavaScriptでロールオーバー */
function btnRollOverForJS(obj){
var img_on="/content/img/btn/btn_on.gif";
var img_off="/content/img/btn/btn_off.gif";
obj.src=(obj.src.indexOf("btn_on")!=-1) ? img_off : img_on;
}
</script>
<form action="#">
<img src="/content/img/btn/btn_off.gif"
width="59" height="18"
alt="サンプルボタン"
onmouseover="btnRollOverForJS(this)" onmouseout="btnRollOverForJS(this)" />
</form>