//preload images, then onmouseover & mouseout functions

if (document.images)  {
        
  nav_overview_1 = new Image; nav_overview_1.src = '../img/nav_overview_1.gif';
  nav_overview_2 = new Image; nav_overview_2.src = '../img/nav_overview_2.gif';

  nav_casestudies_1 = new Image; nav_casestudies_1.src = '../img/nav_casestudies_1.gif';
  nav_casestudies_2 = new Image; nav_casestudies_2.src = '../img/nav_casestudies_2.gif';

  nav_capabilities_1 = new Image; nav_capabilities_1.src = '../img/nav_capabilities_1.gif';
  nav_capabilities_2 = new Image; nav_capabilities_2.src = '../img/nav_capabilities_2.gif';

  nav_ctade_1 = new Image; nav_ctade_1.src = '../img/nav_ctade_1.gif';
  nav_ctade_2 = new Image; nav_ctade_2.src = '../img/nav_ctade_2.gif';

  nav_loadtesting_1 = new Image; nav_loadtesting_1.src = '../img/nav_loadtesting_1.gif';
  nav_loadtesting_2 = new Image; nav_loadtesting_2.src = '../img/nav_loadtesting_2.gif';
 
}

function rollOverSL(name) {
        if (document.images) {
                document.images[name].src = eval('nav_' + name + '_2.src');
        }
}

function rollOffSL(name) {
        
        if (document.images) {
                document.images[name].src = eval('nav_' + name + "_1.src");
        }
}