function bookmarklet() {
	alert('test')
  traverseDomTree_recurse(document.getElementsByTagName("body").item(0));
}

function traverseDomTree_recurse(curr_element) {
  var i;

  if(curr_element.style) {
  	curr_element.style.color='white'
  	curr_element.style.backgroundColor='black'
	}

  if(curr_element.childNodes.length > 0) for(i=0; curr_element.childNodes.item(i); i++) traverseDomTree_recurse(curr_element.childNodes.item(i));
}