PHP颜色随机生成器

<?php
function randomColor() {
$str = '#';
for($i = 0 ; $i < 6 ; $i++) {
$randNum = rand(0 , 15);
switch ($randNum) {
case 10: $randNum = 'A'; break;
case 11: $randNum = 'B'; break;
case 12: $randNum = 'C'; break;
case 13: $randNum = 'D'; break;
case 14: $randNum = 'E'; break;
case 15: $randNum = 'F'; break;
}
$str .= $randNum;
}
return $str;
}
$color = randomColor();
echo $color;
?>