jQuery: How to count table columns?

Answer 1

/**
 * Get number of columns in table.
 * @param {string} table jQuery selector
 * @param {boolean} [malformed=false] whether to inspect each row of malformed table;
 * may take some time for large tables
 * @returns {?number} number of columns in table, null if table not found.
 */
function getTableColumnsCount(table, malformed) {
    malformed = malformed || false;

    var $table = $(table);
    if (!$table.length) {
        return null;
    }

    var rows = $table.children('thead, tfoot, tbody').children('tr');
    if (!malformed) {
        // for correct tables one row is enough
        rows = rows.first();
    }
    var maxCount = 0;
    rows.each(function () {
        var currentCount = 0;
        $(this).children('th, td').each(function () {
            currentCount += this.colSpan;
        });
        maxCount = Math.max(maxCount, currentCount);
    });

    return maxCount;
}

See in action https://jsfiddle.net/kqv7hdg5.

• Takes colspan into account.
• Works for nested tables.
• Works for