code: function(sSource) {
          if(this._elFt) {
              var filter = make("span",{ className: "yui-log-filtergrp" }),
                  check  = make("input", {
                      id: "yui-log-filter-" + sSource + this._sName,
                      className: "yui-log-filter-" + sSource,
                      type: "checkbox",
                      source: sSource
                  }),
                  label  = make("label", {
                      htmlFor: check.id,
                      className: sSource,
                      innerHTML: sSource
                  });
              
  
              // Subscribe to the click event
              Event.on(check,'click',this._onCheckSource,this);
  
              this._filterCheckboxes[sSource] = check;
  
              // Append el at the end so IE 5.5 can set "type" attribute
              // and THEN set checked property
              filter.appendChild(check);
              filter.appendChild(label);
              this._elSourceFilters.appendChild(filter);
              check.checked = true;
          }
      }
docs: Creates a checkbox in the LogReader footer element to filter by source.
  
  @method _createSourceCheckbox
  @param sSource {String} Source name.
  @private