function ChangeTab(form1,form2)
{
    var ele1 = document.getElementById(form1);
    var ele2 = document.getElementById(form2);
    var eleHeader1 = document.getElementById('header1');
    var eleHeader2 = document.getElementById('header2');
    var cont = document.getElementById('modSignUp');
   
    if(form1 == 'joinUp')
    {
        
        cont.style.backgroundImage ="url('../images/sign_up_alt_bgd.gif')";
        eleHeader1.style.fontWeight = 'bold';
         eleHeader2.style.fontWeight = 'normal';
    }
    else{
        cont.style.backgroundImage ="url('../images/sign_up_alt_bgd2.gif')";
         eleHeader2.style.fontWeight = 'bold';
         eleHeader1.style.fontWeight = 'normal';
    }
   
   ele1.style.display='block';
   ele2.style.display='none';
   
}