function showTab(tabToShow, btnToActivate, indx){
    hideTabs();
    turnOffTabs();
    $(tabToShow).style.display = 'block';
    $(btnToActivate).src = ons[indx].src;
}
function hideTabs(){
    var divs = document.getElementsByTagName('DIV');
    var tabs = new Array();
    var j = 0;
    for (i=0; i<divs.length; ++i){
        //if (divs[i].getAttribute('class') == 'tab'){ //doesn't work in IE
        if (divs[i].className == 'tab'){
            tabs[j] = divs[i];
            ++j;
        }
    }
    for (k=0; k<tabs.length; ++k){
        tabs[k].style.display = 'none';
    }
}
function turnOffTabs(){
    var imgs = document.getElementsByTagName('img');
    var bttns = new Array();
    var j = 0;
    for (i=0; i<imgs.length; ++i){
        //if (imgs[i].getAttribute('class') == 'button'){ //doesn't work in IE
        if (imgs[i].className == 'button'){
            bttns[j] = imgs[i];
            ++j;
        }
    }
    for (k=0; k<bttns.length; ++k){
        bttns[k].src = offs[k].src;
    }
}

/* THIS CODE MOVED TO js/activeLink.js 'cus that file also has a window.onload defined
window.onload = function(){
    document.getElementById('overview').style.display = 'block';
}
*/

var ons = new Array(new Image(), new Image(), new Image());
ons[0].src = '../i/landing-pgs/btn_overview_on.gif';
ons[1].src = '../i/landing-pgs/btn_specifications_on.gif';
ons[2].src = '../i/landing-pgs/btn_dowloads_on.gif';

var offs = new Array(new Image(), new Image(), new Image());
offs[0].src = '../i/landing-pgs/btn_overview_off.gif';
offs[1].src = '../i/landing-pgs/btn_specifications_off.gif';
offs[2].src = '../i/landing-pgs/btn_dowloads_off.gif';

function $(elt){
    return document.getElementById(elt)
}