code: function () {
              var placeholder = this.getPlaceholder();
  
              if (placeholder !== undefined  && this.getVal().length === 0 && this.search.hasClass("select2-focused") === false) {
                  this.search.val(placeholder).addClass("select2-default");
                  // stretch the search box to full width of the container so as much of the placeholder is visible as possible
                  this.resizeSearch();
              } else {
                  // we set this to " " instead of "" and later clear it on focus() because there is a firefox bug
                  // that does not properly render the caret when the field starts out blank
                  this.search.val(" ").width(10);
              }
          }
docs: multi