extjs 如何给column 加上提示

<script type="text/javascript"src="${pageContext.request.contextPath }/extjs/examples/simple-widgets/qtips.js"></script>renderer : function(value, metaData, record, rowIndex,colIndex, store) {// provide the logic depending on business rules// name of your own choosing to manipulate the cell// depending upon// the data in the underlying Record object.// metaData.css : String : A CSS class name to add// to the TD element of the cell.// metaData.attr : String : An html attribute// definition string to apply to// the data container element within the table// cell (e.g. 'style="color:red;"').metaData.attr = 'ext:qtip="' + value + '"';return value;}