modulo = 5;

function changebg(obj){
    obj.style.backgroundImage="none";
}
function changebg2(obj){
    obj.style.backgroundImage="url(images/index_03.jpg)";
}
function goleft(){
    tmp = document.getElementById('div1').src;
    document.getElementById('div1').src = document.getElementById('div2r').src;
    document.getElementById('div2r').src = document.getElementById('div3r').src;
    document.getElementById('div3r').src = document.getElementById('div3l').src;
    document.getElementById('div3l').src = document.getElementById('div2l').src;
    document.getElementById('div2l').src = tmp;
}
function goright(){
    tmp = document.getElementById('div1').src;
    document.getElementById('div1').src = document.getElementById('div2l').src;
    document.getElementById('div2l').src = document.getElementById('div3l').src;
    document.getElementById('div3l').src = document.getElementById('div3r').src;
    document.getElementById('div3r').src = document.getElementById('div2r').src;
    document.getElementById('div2r').src = tmp;
}
function getRndmPic(){
    number = Math.floor(Math.random()*modulo) ;
    document.getElementById('div1').src = 'images/img'+(number%modulo)+'.jpg';
    document.getElementById('div2r').src = 'images/img'+((number+1)%modulo)+'.jpg';
    document.getElementById('div3r').src = 'images/img'+((number+2)%modulo)+'.jpg';
    document.getElementById('div3l').src = 'images/img'+((number+3)%modulo)+'.jpg';
    document.getElementById('div2l').src = 'images/img'+((number+4)%modulo)+'.jpg';
}