var currItem = listbox.options[currIndex];
var prevItem = listbox.options[currIndex - 1];
//alert(currItem);
alert(prevItem.text);
listbox.options[currIndex - 1].text = currItem.text;
listbox.options[currIndex - 1].value = currItem.value;
alert(prevItem.text); //两次alert值是不同的
listbox.options[currIndex].text = prevItem.text;
listbox.options[currIndex].value = prevItem.value;
<script type="text/javascript">
window.onbeforeunload=function()
{
alert("onbeforeunload event...");
//return false;
}
</script>
<a href="#" onclick="return true;">测试1</a><br/>
<a href="javascript:void(0)" onclick="return true;">测试2</a><br/& ......
