Would like to put spinner indicator when i start pdfhtml5 and stop when complete

ALIERALEX

Hi - I am using a spinner package to display a spining indicator when the pdf button is pressed. I can't seem to figure out how to get a call bak when it finishes. I tried to put the code in the exportoptions{format:footer} but it didn't get called and I am not sure when I do get that working, that it gets called at the right time. Is there a proper way to do this with action callbacks?

'''
{
extend: 'pdfHtml5',
customize: function(doc) {

                    //ensure doc.images exists
                    doc.images = doc.images || {};

                    //build dictionary
                    doc.images['checkMark'] = getBase64Image(checkMark);
                    //..add more images[xyz]=anotherDataUrl here

                    //when the content is <img src="myglyph.png">
                    //remove the text node and insert an image node
                    for (var i=1;i<doc.content[1].table.body.length;i++) {
                        if ( doc.content[1].table.body[i][1].text == 'true') {
                            //console.log('text of '+i+' row '+doc.content[1].table.body[i][1].text);
                            delete doc.content[1].table.body[i][1].text;
                            doc.content[1].table.body[i][1].image = 'checkMark';
                        }
                        else {
                            doc.content[1].table.body[i][1].text='';
                        }
                    }
                    doc.content[1].table.widths = [ '9%', '2%', '18%', '8%', '12%', '10%', '8%', '8%', '10%', '8%', '2%', '5%'];
                    var cols = [];
                    cols[0] = {text: 'Left part', alignment: 'left', margin:[20] };
                    cols[1] = {text: 'Right part', alignment: 'right', margin:[0,0,20] };
                    var objFooter = {};
                    objFooter['columns'] = cols;
                    doc['footer']=objFooter;
                },
                text: 'PDF',
                title: 'Warner Pacific Insurance Services - Open Submissions Snapshot '+ currentDate,
                orientation: 'landscape',
                footer: true,
                exportOptions: {
                    columns: ':visible' ,
                    format : {
                        header : function (mDataProp, columnIdx) {
                            spinner.spin(target);
                            //console.log('raw'+mDataProp);
                            var htmlText = '<span>' + mDataProp + '</span>';
                            var jHtmlObject = jQuery(htmlText);
                            jHtmlObject.find('span').remove();
                            jHtmlObject.find('option').remove();

                            var newHtml = jHtmlObject.text();
                            console.log('My header for col: '+columnIdx+' > ' + newHtml);
                            if(columnIdx == 19) return 'U R G';
                            if(columnIdx == 7) return 'Group Name';
                            if(columnIdx == 8) return 'Policy Eff Date';
                            if(columnIdx == 10) return 'Status';
                            if(columnIdx == 14) return 'Case Advocate';
                            if(columnIdx == 16) return '# E N R';
                            return newHtml;
                        },

                        footer: function(mDataProp, columnIdx) {
                            console.log('My footer for col: '+columnIdx+' > ' + newHtml);
                           spinner.stop();
                        },
                    },
                    columns: [/*0,*/ 1, /*2, 3, */ 19, /*4, 5, 6,*/ 7, 8, 9, 10, /*11,*/ 12, 13, 14, 15, 16, 17]
                }
            },

'''