var doAlerts=false; // debugging

function changeStyle(whichSheet){
  whichSheet=whichSheet-1; // zero-based
  if(document.styleSheets){
    var c = document.styleSheets.length; // number of stylesheets attached
	// alert(c);
    if (doAlerts) alert('Change to Style '+(whichSheet+1));
    for(var i=0;i<c;i++){
      if(i!=whichSheet){
        document.styleSheets[i].disabled=true;
      } else{
        document.styleSheets[i].disabled=false;
      }
    }
  }
}