Extract Javascript Response Value

I have a table in my webpage with a javascript which convert html table into json code

this is my webpage link
Test (hellotestingmyblog.blogspot.com)

the yellow text is the response code which is generated by javascript…

how can i extract that response value through app and show that in a label…

here is my blocks

and i run this javascript

function tableToJson(table) {
var data = [];
for (var i = 1; i < table.rows.length; i++) {
var tableRow = table.rows[i];
var rowData = {};
for (var j = 0; j < tableRow.cells.length; j++) {
var tableHeader = table.rows[0].cells[j].innerHTML;
var tableData = tableRow.cells[j].innerHTML;
rowData[tableHeader] = tableData;
return data;

	window.onload = function() {
		var table = document.getElementById("myTable");
		var json = tableToJson(table);
		var outputElement = document.getElementById("output");
		outputElement.innerHTML = JSON.stringify(json);

with script open and close tag in the starting and ending point