javascript 访问 webservice

<?xml version="1.0" encoding="UTF-8"?>
<boolean xmlns="http://tempuri.org/">false</boolean>

$.ajax({
    url: "../webService/CommonExternalWebService.asmx/CheckSystemVersionIsBicp",
    dataType: "xml",
    success: function (xml) {
        alert($(xml).find("boolean").text());
    },
    error: function (ex) {
        alert("error:" + ex);
    }
});