jil

<script type="text/javascript">
//  var str='http://taobao.com/?id=123456780';
//  var str='http://taobao.com/&id=123456780'
    var str='http://taobao.com/?shid=123456780&id=0000000'
    var re=/(&id=)([0-9]{5,20})/g;
    var re2=/([?]id=)([0-9]{5,20})/g; 
    var re3=/([0-9]{5,20})/g; 
    newre=str.match(re)
    newre2=str.match(re2)
    if (newre==null && newre2==null) {alert( "商品id不存在" );}else{
        if (newre!=null) {
            itemurl=newre[0];
            itemurl=itemurl.match(re3);
            itemurl=itemurl[0]
            alert(itemurl)
        }else{
            itemurl=newre2[0];
            itemurl=itemurl.match(re3);     
            itemurl=itemurl[0]
            alert(itemurl)
        }
    }   
</script>