var ns4=document.layers;
var ns6=document.getElementById&&!document.all;
var ie4=document.all;

function SearchOnFocus(field) {
  if(field.value=='Tìm kiếm...') {
    field.value = '';
  }
}

function SearchOnBlur(field) {
  if(field.value=='') {
    field.value='Tìm kiếm...';
  }
}