Script {
          directOutput TRUE
          field    MFNode  blocks    IS blocks
  
          eventOut SFInt32 nrLevels  IS nrLevels
          eventIn  SFInt32 showLevel IS showLevel
  
          eventOut SFInt32 level IS level
  
          url "javascript:
              function initialize() {
                  var i = 0;
                  var maxLevels = 0;
                  for(i=0;i<blocks.length;i++) {
                      if((blocks[i].lastLevel+1) > maxLevels) {
                          maxLevels = blocks[i].lastLevel+1;
                      }
                  }
                  nrLevels = maxLevels;
              }