Get number of weekdays in a given month

You don't need to count every day in the month. You already know the first 28 days contain 20 weekdays no matter what. All you have to do is determine the last few days. Change the start value to 29. Then add 20 weekdays to your return value.

function get_weekdays($m,$y) {
$lastday = date("t",mktime(0,0,0,$m,1,$y));
$weekdays=0;
for($d=29;$d<=$lastday;$d++) {
    $wd = date("w",mktime(0,0,0,$m,$d,$y));
    if($wd > 0 && $wd < 6) $weekdays++;
    }
return $weekdays+20;
}

Some basic code:

$month = 12;
$weekdays = array();
$d = 1;

do {
    $mk = mktime(0, 0, 0, $month, $d, date("Y"));
    @$weekdays[date("w", $mk)]++;
    $d++;
} while (date("m", $mk) == $month);

print_r($weekdays);

Remove the @ if your PHP error warning doesn't show notices.

try this one

function getWeekdays($m, $y = NULL){
    $arrDtext = array('Mon', 'Tue', 'Wed', 'Thu', 'Fri');

    if(is_null($y) || (!is_null($y) && $y == ''))
        $y = date('Y');

    $d = 1;
    $timestamp = mktime(0,0,0,$m,$d,$y);
    $lastDate = date('t', $timestamp);
    $workingDays = 0;
    for($i=$d; $i<=$lastDate; $i++){
        if(in_array(date('D', mktime(0,0,0,$m,$i,$y)), $arrDtext)){
            $workingDays++;
        }
    }
    return $workingDays;
}