Get logged in user using ECMA Script

function getWebUserData() {
    $.blockUI();
    // debugger;  
    web = context.get_web();
    currentUser = web.get_currentUser();
    currentUser.retrieve();
    context.load(web);
    context.executeQueryAsync(Function.createDelegate(this, this.onSuccessMethod), Function.createDelegate(this, this.onFailureMethod));
}
function onSuccessMethod(sender, args) {
    userObject = web.get_currentUser();
    loggginname = userObject.get_loginName();
    loggginname = loggginname.split("\\")[1];
    currentUrl = window.location.origin;
    currentUrl = currentUrl + "/";
    var clientContext = new SP.ClientContext(currentUrl);
    empBasicInfoLst = clientContext.get_web().get_lists().getByTitle("EmpBasicInfo");
    spCamlQueryObj = new SP.CamlQuery();
    spQueryGetUserInfo = "<View><Query><Where><Eq><FieldRef Name='Title' /><Value Type='Text'>" + loggginname + "</Value></Eq></Where></Query></View>";
    spCamlQueryObj.set_viewXml(spQueryGetUserInfo);
    empBasicInofColl = empBasicInfoLst.getItems(spCamlQueryObj)
    clientContext.load(empBasicInofColl);
    clientContext.executeQueryAsync(retrieveEmpBasicInfoListItemsSuccess, retrieveEmpBasicInfoListItemsFail);
}