function $$(id){
    return document.getElementById(id);
}
function $t(el){
    el.style.display = el.style.display === 'none' ? '' : 'none';
}

var CURRENT_IMG = 'imgHome';

function changeButtonPic(imgId, show)
{
    var img = $$(imgId);

    if(imgId != CURRENT_IMG)
        if(show)
            img.src = img.src.replace('.','1.');
        else
            img.src = img.src.replace('1.','.');
}