/** Fetch the math */
function fetchMath($sum)
{
if (class_exists('MathRenderer')) {
$math = MathRenderer::getRenderer($sum, array(), MW_MATH_PNG);
} else {
throw new Exception('MathCaptcha requires the Math extension for MediaWiki versions 1.18 and above.');
}
$html = $math->render();
return preg_replace('/alt=".*?"/', '', $html);
}
