table displaying [object Object] in every cell

Question

based on drop down i m displaying table using ajax jquery call.while i m selecting drop down list table is displaying but every cells showing [object Object] instead of data's

 

This my jquery code: 

 

function generateTable(json) {

var $table = $('#tblDynamic');

$table.find('thead').empty()

$table.find('tbody').empty()

if (json && json.length > 0) {

var header = json[0];

var columns = [];

for (var col in header) {

columns.push('<th>' + col + '</th>');

}

$table.find('thead').append('<tr>' + columns.join('') + '</tr>');

var rows = [];

for (var i = 0; i < json.length; i++) {

var row = json[i];

var tds = [];

for (var col in row) {

tds.push('<td>' + row + '</td>');

}

rows.push('<tr>' + tds.join() + '</tr>');

}

$table.find('tbody').append(rows.join(''));

}

}