$(document).ready(function () {
  var search = $('input#inputtext'); // input text field
  var default_value = search.val();
  search.focus(function(){
    if ($.trim($(search).val()) == default_value) search.val('');
  });
  search.blur(function(){
    if ($.trim($(search).val()) == '') search.val(default_value);
  });
});