求助如何用JS模拟出按钮点击的效果

[shellmark]

<img align="absmiddle" src="find.gif" id="btnSearch">
当点击时，图片会有一个很小的错位，但马上就恢复原样

[tata_1980]

step1:
<style>
<!--
.popshadow{
position:relative;
left:-5;
top:-5;
filter:shadow(silver,direction=135)
}
-->
</style>

<script language="JavaScript1.2">

/*
Pop-up Image Script-
?Dynamic Drive (www.dynamicdrive.com)
For full source code, installation instructions,
100's more DHTML scripts, and Terms Of
Use, visit dynamicdrive.com
*/

function updownshadow(){
if (event.srcElement.className=="popshadow"){
tempobject=event.srcElement
if (event.type=="mousedown"){
tempobject.filters[0].enabled=false
tempobject.style.left=tempobject.style.top=0
}
else{
tempobject.filters[0].enabled=true
tempobject.style.left=tempobject.style.top=-5
}
}
}

if (document.all){
document.body.onmousedown=updownshadow
document.body.onmouseup=updownshadow
}

</script>

[tata_1980]

step2:
<img src="yourimage.gif" class="popshadow">

[tata_1980]

把step1的内容放入head中

[孟子E章]

<img src="http://expert.csdn.net/images/csdn.gif" style="cursor:hand;border:0px solid red" onmousedown="this.style.border='2px solid #FFFFFF'" onmouseup="this.style.border='0px solid #FFFFFF'">