//help functions
//---------------------------------
var hSel = 'help-intro';

function help() {
  var x = byId('help');
  var y = byId('help-link');
  if(x.className == 'h-hide') {
    var teaser = byId('new-version-teaser');
    if(teaser) teaser.parentNode.removeChild(teaser);
    x.className = 'h-show';
    y.innerHTML = 'Hide Help';
  }
  else {
    x.className = 'h-hide';
    y.innerHTML = 'Help';
  }
}
function about() {
  switchHelp('help-about');
  if(byId('help').className == 'h-hide') help();
}
function keys() {
  switchHelp('help-keys');
  if(byId('help').className == 'h-hide') help();
}
function versionHistory() {
  switchHelp('help-hist');
  if(byId('help').className == 'h-hide') help();
}
function switchHelp(id) {
  if(id == hSel) return;
  var txt = byId('help-text');
  if(txt.scrollTop) txt.scrollTop = 0;
  byId(hSel).className = 'h-hide';
  byId('a-'+hSel).className = 'h-show';
  hSel = id;
  byId(id).className = 'h-show';
  byId('a-'+id).className = 'help-selected';
}