How to get the focused Tab in TabPanel ?

public boolean showInputFile{get;set;}
 String tabInFocus = System.currentPageReference().getParameters().get('tab');

public String getTabInFocus() {

    if(tabInFocus=='name2')
    {
    showInputFile=true;

    }
    else
    {
    showInputFile=false;
    }


    return tabInFocus;
    }
    public void setTabInFocus( String s ) {
    this.tabInFocus = s;
    system.debug('*****tab in foucs *****'+s);
    if(s=='name2')
    {
    showInputFile=true;

    }
    else
    {
    showInputFile=false;
    }

    }