<script type="text/javascript">

function chkResetTop() 

{

var obj = document.getElementById("top_search");

obj.style.backgroundImage = '';

obj.focus();

}  

</script>

<input class="mem_input" id="top_search" onkeydown="chkResetTop();" style=" background-image: url(/myfile/images/search.gif); width: 105px; background-repeat:no-repeat; background-color:#f1f2f4" onfocus="chkResetTop();">