report opens in a new tab in IE9

[balllei]

I have a dashboard web application integrated with cognos10.1 , the report in dashboard can drill down to the next level report, and the next level report has a return button to return to the previous one. It works fine in IE9 compatibility mode, but in normal mode when the return button is clicked, the report will open a new tab for the previous report instead of opening in the original web page. The return button is written in the cognos report with the following js:
function  executeReturnLink()
{
     var fW = (typeof getFormWarpRequest == "function" ? getFormWarpRequest() : document.forms["formWarpRequest"]);
    if ( !fW || fW == undefined) 
    {
        fW = ( formWarpRequest_THIS_ ? formWarpRequest_THIS_ : formWarpRequest_NS_ );
    }

    var preFix = "";
    if (fW.elements["cv.id"])
    {
        preFix = fW.elements["cv.id"].value;
    }   
    var nameSpace = 'oCV' + preFix;
    var cViewer= eval(nameSpace);

   cViewer.rvMainWnd.executePreviousReport(-1);   

Does anyone know how to fix this? It bothers me for a long time, thank you very much.