var previousSelection = null;
  //Image Groups
  var COMPANY = '0';
  var HISTORY = '1';
//  var TEAM = '2';
//  var INVESTOR = '3';
  var NONE = null;

  //Image States
  var UP = '0';
  var DOWN = '1';

  /* Set nested array in following format
   * 0 = up
   * 1 = down
   */
  var jimages = [
    ['images/companygrey.gif', 'images/companyblue.gif'],
    ['images/historygrey.gif', 'images/historyblue.gif'],
//    ['images/teamgrey.gif', 'images/teamblue.gif'],
//    ['images/investorgrey.gif', 'images/investorblue.gif'],
  ];

  function revert(){highlight(previousSelection);}

  function select(selection){
    highlight(selection);
    switch(selection){
      case '0':
        previousSelection = COMPANY;
        break;
      case '1':
        previousSelection = HISTORY;
        break;
//      case '2':
//        previousSelection = TEAM;
//        break;
//      case '3':
//        previousSelection = INVESTOR;
//        break;
      default:
        previousSelection = null;
        break;
    }
  }

  function highlight(selection){
    //set all tabs to thier respective up -- inactive state
    document.Companys.src= jimages[eval(COMPANY)][eval(UP)];
    document.History.src= jimages[eval(HISTORY)][eval(UP)];
//    document.Team.src= jimages[eval(TEAM)][eval(UP)];
//    document.Investor.src= jimages[eval(INVESTOR)][eval(UP)];
    //set the the selected tab to its down -- active state
    switch(selection){
      case '0':
        document.Companys.src = jimages[eval(COMPANY)][eval(DOWN)];
        break;
      case '1':
        document.History.src = jimages[eval(HISTORY)][eval(DOWN)];
        break;
//      case '2':
//        document.Team.src = jimages[eval(TEAM)][eval(DOWN)];
//        break;
//      case '3':
//        document.Investor.src = jimages[eval(INVESTOR)][eval(DOWN)];
//        break;
      default:
        break;
    }
  }