<script>
function testFun()
{
if(window.name=="cartlist") window.name="";
var popup=window.open("","cartlist");
}</script>
<input type=button value=test onclick="testFun();"/>
function testFun()
{
if(window.name=="cartlist") window.name="";
var popup=window.open("","cartlist");
}</script>
<input type=button value=test onclick="testFun();"/>
window.open("javascript:if(window.document.body) {window.focus();alert('已有该名字的窗口');};else {alert('该名字的窗口还没有打开');}","aaaa");
</script>