[miniature]

Yes, something like that: "'document.getElementById(...)' empty or doesn't object"

[Nico]

Hm, could you post your whole code?

[miniature]

Code:

function check_login() {
  document.getElementById('chars_num_login_username').innerHTML = document.getElementById('username_login').value.length;
  document.getElementById('chars_num_login_password').innerHTML = document.getElementById('password_login').value.length;

  if((!check('username_login')) || (!check('password_login'))) {
    document.getElementById('submit_login').disabled = true;
  }
  else {
    document.getElementById('submit_login').disabled = false;
  }
}

Code:

<form method="post" action="{$_SERVER['PHP_SELF']}">
<u><strong>login</strong></u><br />
<div style="width:10%;float:right;line-height:22px;">username:<br />password:</div>
<div style="width:20%;float:right;">
<input type="text" name="username_login" id="username_login" onkeyup="javascript:check_login();" /><br />
<input type="password" name="password_login" id="password_login" onkeyup="javascript:check_login();" autocomplete="off" /><br />
<input type="submit" name="submit_login" id="submit_login" value=" login " style="height:25px;" disabled="disabled" />
</div>
<div class="opens_desc">
<div class="opens_chars"><strong><span id="chars_num_login_username">0</span></strong> chars</div></div>
<div class="opens_desc">
<div class="opens_chars"><strong><span id="chars_num_login_password">0</span></strong> chars</div></div>
</form>

(same to register [replace "login" with "register"..])