var rand = Math.floor(Math.random()*4) + 1;

window.onload = function() {
	getElementsByClassName("hasbgimg")[0].className += " container"+rand;
	if(rand==4) {
		document.body.style.background = "#747474";
	} else if(rand==1) {
		getElementsByClassName("containerin")[0].className += " rf2";
	}
}

function getElementsByClassName (className) {
  var children = document.getElementsByTagName('*') || document.all;
  var elements = new Array();
  for (var i = 0; i < children.length; i++) {
    var child = children[i];
    var classNames = child.className.split(' ');
    for (var j = 0; j < classNames.length; j++) {
      if (classNames[j] == className) {
        elements.push(child);
        break;
      }
    }
  }
  return elements;
}