How to generate passoword in php with specific length?

function generate_password( $length = 8 ) {
  $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  $password = substr( str_shuffle( $chars ), 0, $length );
  return $password;
 }

Alpha Space Validation in JS

Enter text file allow allphabi & space only
function alpha_space_validation(arg){
 var valReg = /^[A-Za-z ]+$/;
 if(valReg.test( arg ) ) {
  return false;
 } else {
  return true;
 }
}