generate random password

function rand_string( $length ) {
	$str = "";
	$chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

	$size = strlen( $chars );
	for( $i = 0; $i < $length; $i++ ) {
		$str .= $chars[ rand( 0, $size - 1 ) ];
	}

	return $str;
}
//and call the function this way:
$mypass = rand_string(10);var btn = document.getElementById("btn");

btn.addEventListener("click", function generate() {
  var generatePassword = "";
  var password = document.getElementById("password");
  var characters =
    "abcdefghijklmnopqrstuvwxyz1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ!@#$%^&*?";

  for (var i = 0; i < 10; i++) {
    generatePassword += characters.charAt(
      Math.floor(Math.random() * characters.length)
    );
  }
  password.innerHTML = generatePassword;
});