Tutorial raspando a câmara.

(function ($) {
    $.fn.tableToJSON = function (opts) {

        // Set options
        var defaults = {
            ignoreColumns: [],
            onlyColumns: null,
            ignoreHiddenRows: true,
            headings: null
        };
        opts = $.extend(defaults, opts);

        var notNull = function (value) {
            if (value !== undefined && value !== null) {
                return true;
            }
            return false;
        };

        var ignoredColumn = function (index) {
            if (notNull(opts.onlyColumns)) {
                return $.inArray(index, opts.onlyColumns) === -1;
            }
            return $.inArray(index, opts.ignoreColumns) !== -1;
        };

        var arraysToHash = function (keys, values) {
            var result = {};
            $.each(values, function (index, value) {
                if (index < keys.length) {
                    result[keys[index]] = value;
                }
            });
            return result;
        };

        var rowValues = function (row) {
            var result = [];
            $(row).children("td,th").each(function (cellIndex, cell) {
                if (!ignoredColumn(cellIndex)) {
                    var override = $(cell).data("override");
                    var value = $.trim($(cell).text());
                    result[result.length] = notNull(override) ? override : value;
                }
            });
            return result;
        };

        var getHeadings = function (table) {
            var firstRow = table.find("tr:first").first();
            return notNull(opts.headings) ? opts.headings : rowValues(firstRow);
        };

        var construct = function (table, headings) {
            var result = [];
            table.children("tbody,*").children("tr").each(function (rowIndex, row) {
                if (rowIndex !== 0 || notNull(opts.headings)) {
                    if ($(row).is(":visible") || !opts.ignoreHiddenRows) {
                        result[result.length] = arraysToHash(headings, rowValues(row));
                    }
                }
            });
            return result;
        };

        // Run
        var headings = getHeadings(this);
        return construct(this, headings);
    };
})(jQuery);

var table = $("#grid");
var object = table.tableToJSON();
var json = JSON.stringify(object);