Applying icon in place of text for cutom buttons

SKC

I have placed a custom Excel button for my datatable.

 buttons: [

            {

                text: 'Excel',

                action: function ( e, dt, node, config ) {

                    ExportRequests();
                }

            }

Instead of the text I want to apply icon on this button. How can I achieve it?

SKC

Got it working by modifying as follows :

 "buttons": [
        {
            text: '<span class="glyphicon glyphicon-file" data-toggle="tooltip" title="Export To Excel"/>',
             action: function ( e, dt, node, config ) {
                 ExportRequests();
             }
         }