rem: return ((element.offsetTop+element.offsetHeight)-this.ycomp) / element.offsetHeight; 
add: return ((this.offset[1]+element.offsetHeight)-this.ycomp) / element.offsetHeight; 
context:   overlap: function(mode, element) {      if(!mode) return 0;      if(mode == 'vertical')       return ((element.offsetTop+element.offsetHeight)-this.ycomp) / element.offsetHeight;    if(mode == 'horizontal')      return ((element.offsetLeft+element.offsetWidth)-this.xcomp) / element.offsetWidth;  },
meta: 4053	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/4053/5fec2a22b3ffc5a2da695845e2922706e29402bb/prototype-ext.js/buggy/src/prototype-ext.js