Convert JS array to HTML table

array2table.js

// build HTML table data from an array (one or two dimensional)
function generateTable(data) {
    var html = '';

    if (typeof (data[0]) === 'undefined') {
        return null;
    }

    if (data[0].constructor === String) {
        html += '<tr>\r\n';
        for (var item in data) {
            html += '<td>' + data[item] + '</td>\r\n';
        }
        html += '</tr>\r\n';
    }

    if (data[0].constructor === Array) {
        for (var row in data) {
            html += '<tr>\r\n';
            for (var item in data[row]) {
                html += '<td>' + data[row][item] + '</td>\r\n';
            }
            html += '</tr>\r\n';
        }
    }

    if (data[0].constructor === Object) {
        for (var row in data) {
            html += '<tr>\r\n';
            for (var item in data[row]) {
                html += '<td>' + item + ':' + data[row][item] + '</td>\r\n';
            }
            html += '</tr>\r\n';
        }
    }

    return html;
}