var arrayRow = document.getElementsByTagName( "tr" );
var re1 = new RegExp("Package", "i");
var re2 = new RegExp("Header", "i");

for( var i=0; i<arrayRow.length; i++ ) {
  if( arrayRow[i].className.match(re1) && !arrayRow[i].className.match(re2) ) {
    arrayRow[i].onmouseover = function() {
      this.style.backgroundColor = "yellow";
    }
    arrayRow[i].onmouseout = function() {
      this.style.backgroundColor = "white";
    }
  }
}