Find Which Transaction is currently Running

SELECT s_tst.[session_id],
   s_es.[login_name] AS [Login Name],
   S_tdt.[database_transaction_begin_time] AS [Begin Time],
   s_tdt.[database_transaction_log_record_count] AS [Log Records],
   s_tdt.[database_transaction_log_bytes_used] AS [Log Bytes],
   s_tdt.[database_transaction_log_bytes_reserved] AS [Log Reserved],
   s_est.[text] AS [Last T-SQL Text],
   s_eqp.[query_plan] AS [Last Query Plan]
FROM sys.dm_tran_database_transactions s_tdt
   JOIN sys.dm_tran_session_transactions s_tst
      ON s_tst.[transaction_id] = s_tdt.[transaction_id]
   JOIN sys.[dm_exec_sessions] s_es
      ON s_es.[session_id] = s_tst.[session_id]
   JOIN sys.dm_exec_connections s_ec
      ON s_ec.[session_id] = s_tst.[session_id]
   CROSS APPLY sys.dm_exec_sql_text (s_ec.[most_recent_sql_handle]) AS s_est
   OUTER APPLY sys.dm_exec_query_plan (s_ec.[most_recent_sql_handle]) AS s_eqp
ORDER BY [Begin Time] ASC;

Core AJAX Call from Page

Javascript

function newXMLHttpRequest() {
    var xmlreq = false;
    if (window.XMLHttpRequest) {
        xmlreq = new XMLHttpRequest();
    } else if (window.ActiveXObject) {
        // Try ActiveX
        try {
            xmlreq = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e1) {
            // first method failed 
            try {
                xmlreq = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e2) {
                // both methods failed 
            }
        }
    }
    return xmlreq;
}

function GetUserInfo(PageURL) {
    var req = newXMLHttpRequest();

    req.open("POST", PageURL, true);
    req.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    req.setRequestHeader("content-length", "0"); req.send('');

    req.onreadystatechange = function() {
        if (req.readyState == 4) {
            if (req.status == 200) {
                alert(req.responseText.toString());
            }
        }
    }
}

Page Method

Code in aspx page :

[System.Web.Services.WebMethod]
public static string CheckUserAvailability(string sUserId, string sUserName)
{
    return CommonFunctions.CheckUserAvailability(sUserId, sUserName);
}

HTML :
<a href="#" onclick="CheckAvailability()">Check User Availability</a>
<span id="lblCheck"></span>

Javascript :

function CheckAvailability() {
    PageMethods.CheckUserAvailability(document.getElementById('<%= hdnCurrentUserId.ClientID %>').value, document.getElementById('<%= txtUserName.ClientID %>').value, OnSucceededUser, OnFailedUser);

    return false;
}

function OnSucceededUser(result, userContext, methodName) {
    document.getElementById('lblCheck').innerHTML = result;
    return;
}

function OnFailedUser(error, userContext, methodName) {
    return;
}