docs: function createHeader() {
      var wrapStr = '',
          headerShowStr = '';
      if (!this.options.showHeader) headerShowStr = 'style="display:none;"';
      var htmlStr = '<div class="u-grid-header" id="' + this.options.id + '_header" ' + headerShowStr + '><div class="u-grid-header-wrap" id="' + this.options.id + '_header_wrap" data-role="resizable" ' + wrapStr + '>';
      if (this.options.columnMenu) {
          htmlStr += '<div class="u-grid-header-columnmenu uf uf-navmenu-light"></div>';
      }
      if (this.options.multiSelect || this.options.showNumCol) {
          htmlStr += '<div id="' + this.options.id + '_header_left" class="u-grid-header-left" style="width:' + this.leftW + 'px;">';
          if (this.options.multiSelect) {
              if (gridBrowser.isIE8) {
                  //htmlStr += '<div class="u-grid-header-multi-select" style="width:' + this.multiSelectWidth + 'px;"><input class="u-grid-multi-input"   type="checkbox" id="' + this.options.id + '_header_multi_input"></div>'
                  htmlStr += '<div class="u-grid-header-multi-select" style="width:' + this.multiSelectWidth + 'px;"><span class="u-grid-checkbox-outline" id="' + this.options.id + '_header_multi_input"><span class="u-grid-checkbox-tick-outline"></span></span></div>';
              } else {
                  //htmlStr += '<div class="u-grid-header-multi-select  checkbox check-success" style="width:' + this.multiSelectWidth + 'px;"><input  class="u-grid-multi-input"  type="checkbox" id="' + this.options.id + '_header_multi_input"><label for="' + this.options.id + '_header_multi_input"></label></div>'
                  htmlStr += '<div class="u-grid-header-multi-select  checkbox check-success" style="width:' + this.multiSelectWidth + 'px;"><span class="u-grid-checkbox-outline" id="' + this.options.id + '_header_multi_input"><span class="u-grid-checkbox-tick-outline"></span></span></div>';
              }
          }
          if (this.options.showNumCol) {
              htmlStr += '<div class="u-grid-header-num" style="width:' + this.numWidth + 'px;"></div>';
          }
          htmlStr += '</div>';
      }
      htmlStr += this.createHeaderTableFixed();
      htmlStr += this.createHeaderTable();
      htmlStr += '</div>';
      htmlStr += this.createHeaderDrag();
      htmlStr += '</div>';
      return htmlStr;
  }