<select id="s1" multiple="multiple">
<option value="1" onclick="alert(1);">1</option>
<option value="2" onclick="alert(2);">2</option>
</select>

<select id="s2" multiple="multiple">
<option value="1" >1</option>
</select>
<script>
document.getElementById('s2').onclick = function(e){
var evt = window.event || e;
var target = evt.srcElement || evt.target;
alert(target.tagName);
}
</script>

<select id="s1" multiple="multiple">
<option value="1" title="tips">1</option>
</select>