如何去掉图片点击后的超级链接产生的虚框问题

<a onfocus=this.blur() href="javascript:void(0)" class="l-button" style="width:80px" onclick='log_1()'>
<img id="img_a" border=0 align="middle" src="login_image/a_1.jpg" alt="没有图片！"> </img>
</a>

onfocus=this.blur()

<public:attach event="onfocus" onevent="example()" />
<script language="javascript">
function example(){
this.blur();
}
</script>

<style>
a {behavior:url(1.htc)}
area {behavior:url(1.htc)}
</style>