function activateTab(tabId) {
    var i = 1;

    //deactivate all tabs
    var iteratedTab = document.getElementById('tab_' + i);
    var iteratedTabPage = document.getElementById('tabpage_' + i);
    while (iteratedTab != null) {
        iteratedTab.className = iteratedTab.className.replace(' active', '');
        if (iteratedTabPage != null) {
            iteratedTabPage.className = iteratedTabPage.className.replace(' active', '');
        }
        else {
            alert('Corresponding tabpage not found');
        }

        //iteratedTab through tabs
        i = i + 1;
        iteratedTab = document.getElementById('tab_' + i);
        iteratedTabPage = document.getElementById('tabpage_' + i);
    }

    //activate tab
    var activeTab = document.getElementById('tab_' + tabId);
    var activeTabPage = document.getElementById('tabpage_' + tabId);
    if (activeTab != null) {
        activeTab.className = activeTab.className + ' active';
    }
    if (activeTabPage != null) {
        activeTabPage.className = activeTabPage.className + ' active';
    }
    //document.getElementById('ctl00_cpDetail__tId').value = tabId;
    
    return true;
}

function switchTab(tabId) {
    document.getElementById('ctl00_cpDetail__tId').value = tabId;
    window.postback();
}