function getElt() {
  if (document.all) { // IE4+
    var elt = document.getElementById(getElt.arguments[0]);
    // Extra code to skip the LAYER for Netscape 4 with the same name which causes elt to be an array
    if (elt.length) {
      return elt[0];
    } else {
      return elt;
    }
  } else if (document.layers) { //NS4
    var currentLayer = document.layers[getElt.arguments[0]];

    for (var i = 1; i < getElt.arguments.length && currentLayer; i++) {
       currentLayer = currentLayer.document.layers[getElt.arguments[i]];
    }

    return currentLayer;
  } else if (document.getElementById) { // NS6   
    return document.getElementById(getElt.arguments[0]);
  }
}

function changeTab(allBlocks, curBlock) {  
  //Create an array with all blockids
  var arrayOfBlocks;
  var objtable;
  arrayOfBlocks = allBlocks.split(',');
  
  //Loop through all the block ids
  for (var i=0; i < arrayOfBlocks.length; i++) {
    objtable = getElt(arrayOfBlocks[i]);
    if (arrayOfBlocks[i] == curBlock) {
      //Display this block
      objtable.style.display = 'block';
    } else {
      //Hide this block
      objtable.style.display = 'none';
    }   
   }
 
  return false;
}