var currbutton = '';

function setclass(tochange,chclass) { 
  document.getElementById(tochange).setAttribute('class',chclass); // ie fails
  document.getElementById(tochange).className=chclass; 
}

function mapclick(button) {

  if (currbutton) {
    setclass('but' + currbutton,'deactive');
    if (currbutton != 'no') {
      setclass('pic' + currbutton,'nooverlay');
    }
  } else {
    setclass('butno','deactive');
  }

  setclass('but' + button,'active');
  if (button != 'no') {
    setclass('pic' + button,'overlay');
  }
  currbutton = button;

  setclass('keyimg', 'mapkey' + button);
}

function regesc(str) {
    return str.replace(/[-[\]{}()*+?.\\^$|,#\s]/g, "\\$&");
};

function changememe() {

  var tochange = 'my home town'; 
  var htmldata;

  if (document.getElementById('hmpu').innerHTML == tochange) {
    document.getElementById('hmpu').innerHTML = urlhtml;
    htmldata = document.getElementById('memehtml').innerHTML;
    document.getElementById('memehtml').innerHTML = htmldata.replace(new RegExp(tochange),urlhtmlesc); 
  } else {
    document.getElementById('hmpu').innerHTML = tochange;
    htmldata = document.getElementById('memehtml').innerHTML;
    document.getElementById('memehtml').innerHTML = htmldata.replace(new RegExp(regesc(urlhtmlesc)),tochange);
  }
}