$(function() {
    $('input[id*=txtSearch]').val("Enter the keyword");
    $('input[id*=txtSearch]').focus(
                 function() {
                     if ($(this).val() == "Enter the keyword") $(this).val("");
                 }
                );

                 $('input[id*=txtSearch]').blur(
                 function() {
                     if ($(this).val() == "") $(this).val("Enter the keyword");
                 }
        );
    $('input[id*=txtSearch]').keypress(
     function(e) {
         if (e.which == '13') {
             search();
         }

     }
   );
})

 function search() {
     //window.location.href = "/search.aspx?key=" + $('input[id*=txtSearch]').val();
 }
 function searchvn() {
    // window.location.href = "/tim-kiem.aspx?key=" + $('input[id*=txtSearch]').val();
 }