function popupError() {
   
    var lblError = null;
    if (document.getElementById)
        lblError = document.getElementById('ctl00_cphDetail_lblErrorMessage');
    else if (document.all)
       lblError = document.all['ctl00_cphDetail_lblErrorMessage'];
       
    if (lblError){
        if (lblError.outerText) {
            if (lblError.outerText != '') {
               alert(lblError.outerText)
            }
        } else {
            if (lblError.innerHTML != '') {
               alert(lblError.innerHTML )
            }
        }
    }

}