Question

Can someone help me make a simple javascript to get element body so I can alternate its style to change background images every X seconds?

Answer 1

Set a function to switch backgrounds and add an interval to do it.
Backgrounds are contained in array bgArr.

bgArr = ['images/bg1.jpg', 'anotherdir/bg2.jpg', 'otherone/bg3.jpg'];
bgCur = 0;
backgroundSwitch = function()
{
    if (bgCur == bgArr.length) bgCur = 0;
    document.body.style.backgroundImage = 'url('+ bgArr[bgCur++]+ ')';
}
window.setInterval(backgroundSwitch, 30000); // Switch every 30 seconds.