<!-- Collection of code snippets by Arne Vajhøj -->
<!-- posted to eksperten.dk, usenet and other places (2002-now) -->
<?php
function insert($con, $tbl, $ar = array()) {       
        $values = implode(',', array_fill(0, count($ar), '?'));
        $keys = implode(',', array_keys($ar));
        $sql = 'INSERT INTO ';
        $sql .= $tbl;
        $sql .= ' (';
        $sql .= $keys;
        $sql .= ') ';
        $sql .= 'VALUES ';
        $sql .= '(';
        $sql .= $values;
        $sql .= ')';
        echo $sql;
        $stmt = $con->prepare($sql);
        $types = implode('', array_map(function($v) { return is_int($v) ? 'i' : 's'; }, array_values($ar)));
        call_user_func_array(array($stmt, 'bind_param'), array_merge(array($types), array_map(function(&$v) { return $v; }, array_values($ar))));
        $stmt->execute();
        $stmt->close();
}

$con = new mysqli('localhost', 'root', '', 'Test');
insert($con, 't1', array('f1' => 12345, 'f2' => 'X'));
$con->close();
?>