function showimg(id) 
{
       var e = document.getElementById(id);
          e.style.display = 'inline';
}

    function offimg(id) 
{
       var e = document.getElementById(id);
          e.style.display = 'none';
}

    function show(id) 
{
       var e = document.getElementById(id);
          e.style.display = 'inherit';
}

    function hide(id) 
{
       var e = document.getElementById(id);
          e.style.display = 'none';
}

    function popup(mylink, windowname)
{
      if (! window.focus)return true;
         var href;
      if (typeof(mylink) == 'string')
            href=mylink;
      else
            href=mylink.href;
            window.open(href, windowname, 'width=600,height=600,scrollbars=yes');
      return false;
}

function checkForm()
{
   var cUserName, cPassword, cCheckPassword, cEmail, cCheckEmail;
   with(window.document.registerForm)
   {
      cUserName    = registerUsername;
      cPassword   = registerPassword;
      cCheckPassword = checkRegisterPassword;
      cEmail = registerEmail;
	  cCheckEmail = checkRegisterEmail;
   }
   
    if(trim(cUserName.value) == '')
   {
      show(invalidUsername);
      cUserName.focus();
      return false;
   }
   else if(trim(cPassword.value) == '')
   {
      alert('Please enter a password.');
      cPassword.focus();
      return false;
   }
}
function trim(str)
{
   return str.replace(/^\s+|\s+$/g,'');
}