如何从php中生成的数组获取javascript中的长度？

Question

I use jQuery to call a php function and return an array. Here is the php code:

  $users = array();
  $user = array();

  $user["fname"] = "Juan";
  $user["lname"] = "Perez";
  $user["uname"] = "jperez";
  $user["passwd"] = "passwd1234";
  $user["rights"] = array(
  "mod_own" => true,
  "view_all" => false,
  "mod_all" => true,
  "mod_proj" => false,
  "mod_users" => true
  ); 

  $users[1] = $user;

  $user["fname"] = "Pedro";
  $user["lname"] = "Rodriquez";
  $user["uname"] = "pedror";
  $user["passwd"] = "passwd456+";
  $user["rights"] = array(
  "mod_own" => false,
  "view_all" => true,
  "mod_all" => false,
  "mod_proj" => true,
  "mod_users" => false
  ); 

  $users[1] = $user;
  $ret["users"] = $users;
  $ret["error"] = "";

  echo json_encode($ret);

This is just a test code of what I really want to return. The thing is that I know that users has a length 2 here, but in the real applicaction I won't know that. I want to check its length. In the javascript that calls this function the returning object is call obj. If I say

obj.users[1]['fname']

I get the correct name and everything. What I don't know how to do is check the length of users. I have tried obj.users.length but it doesn't work.

How do I check that?

EDIT:

To see the length I used this code:

document.getElementById("debug").innerHTML="N de users is " + obj.users.length;

I got "N de users is undefined"

Answer 1

You're setting $users[1] twice without setting $users[0] . This will output an Object , which does not have a length property. Instead of specifying the index directly, just push your content into $users : $users[] = $user .