CRM 2011 - Get Current User (not Owner) to see which Teams they are on in JavaScript

I am trying to use the code below I found in another thread to get the Current User who is logged in, not the Owner of the record.  Does anyone know how I can tweak the code below to change this?  I tried replacing the references to "ownerid" with Xrm.Page.context.getUserId(), but I have not had any luck. I am not sure how to return the GUID from the getUserId() method to be able to use it.  I imagine it has to do with arrays, but this is a new concept to me.  Thanks for any and all your help!

function GetCurrentUserTeams() {

    debugger;
    var lookup = Xrm.Page.getAttribute("ownerid").getValue();

    var OwnerID;
    var OwnerName;

    if (lookup != null && lookup[0] != null) {
        OwnerName = lookup[0].name;
        OwnerID = lookup[0].id;
    }

    var xml = "" +"<?xml version=\"1.0\" encoding=\"utf-8\"?>" +"<soap:Envelope xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\">" +
    GenerateAuthenticationHeader() +" <soap:Body>" +" <RetrieveMultiple xmlns=\"http://schemas.microsoft.com/crm/2007/WebServices\">" +" <query xmlns:q1=\"http://schemas.microsoft.com/crm/2006/Query\" xsi:type=\"q1:QueryExpression\">" +" <q1:EntityName>team</q1:EntityName>" +" <q1:ColumnSet xsi:type=\"q1:ColumnSet\">" +" <q1:Attributes>" +" <q1:Attribute>name</q1:Attribute>" +" </q1:Attributes>" +" </q1:ColumnSet>" +" <q1:Distinct>false</q1:Distinct>" +" <q1:LinkEntities>" +" <q1:LinkEntity>" +" <q1:LinkFromAttributeName>teamid</q1:LinkFromAttributeName>" +" <q1:LinkFromEntityName>team</q1:LinkFromEntityName>" +" <q1:LinkToEntityName>teammembership</q1:LinkToEntityName>" +" <q1:LinkToAttributeName>teamid</q1:LinkToAttributeName>" +" <q1:JoinOperator>Inner</q1:JoinOperator>" +" <q1:LinkCriteria>" +" <q1:FilterOperator>And</q1:FilterOperator>" +" <q1:Conditions>" +" <q1:Condition>" +" <q1:AttributeName>systemuserid</q1:AttributeName>" +" <q1:Operator>Equal</q1:Operator>" +"<q1:Values>" +
    //code to get the owner "<q1:Value xsi:type=\"xsd:string\">" + OwnerID + "</q1:Value>" +"</q1:Values>" +" </q1:Condition>" +" </q1:Conditions>" +" </q1:LinkCriteria>" +" </q1:LinkEntity>" +" </q1:LinkEntities>" +" </query>" +" </RetrieveMultiple>" +" </soap:Body>" +"</soap:Envelope>" +"";
    var xmlHttpRequest = new ActiveXObject("Msxml2.XMLHTTP");
    xmlHttpRequest.Open("POST", "/mscrmservices/2007/CrmService.asmx", false);
    xmlHttpRequest.setRequestHeader("SOAPAction", "http://schemas.microsoft.com/crm/2007/WebServices/RetrieveMultiple");
    xmlHttpRequest.setRequestHeader("Content-Type", "text/xml; charset=utf-8");
    xmlHttpRequest.setRequestHeader("Content-Length", xml.length);
    xmlHttpRequest.send(xml);
    var resultXml = xmlHttpRequest.responseXML;
    //alert(resultXml.xml);

    // Save all entity nodes in an array.
    var entityNodes = resultXml.selectNodes("//RetrieveMultipleResult/BusinessEntities/BusinessEntity");

    var teamnames = new Array();
    var teamids = new Array();

    for (var i = 0; i < entityNodes.length; i++) {

        var entityNode = entityNodes[i];
        var teamidNode = entityNode.selectSingleNode("q1:teamid");
        var teamNode = entityNode.selectSingleNode("q1:name");
        var teamid = (teamidNode == null) ? null : teamidNode.text;
        var team = (teamNode == null) ? null : teamNode.text;

        teamnames[i] = team;
        teamids[i] = teamid;
    }

    alert(teamnames);
}