Open dialog jquery based on a list of users

I'm doing a modal window with jquery dialog to update users, but only the dialog of the first user I have in the list opens.

What I want is to open the dialog to fill in the fields of the form that I have inside, with the data of each individual user.

The code generated by the user table is as follows:

public function generaTabla($arreglo_info, $arreglo_col,$name){
  $aux = json_decode(json_encode($arreglo_info),TRUE);
  $th = array_keys($aux[0]);
  $cont = 0;
  $tabla = "<table>";
  $tabla.="<tr>";
  foreach ($th as $key => $value) {
    if ($value!="id_usuario") {
      $tabla.="<th>".$value."</th>";
    }
  }
  foreach ($arreglo_col as $col => $value) {
    $tabla.="<th>".$value."</th>";
  }
  $tabla.="</tr>";
  foreach ($aux as $fila) {
    $tabla.="<tr>";
    foreach ($fila as $col => $valor) {
      if ($col!="id_usuario") {
        $tabla.="<td>".$valor."</td>";
      }
    }
    foreach ($arreglo_col as $col => $value) {
      switch ($value) {
        case 'Actualizar':
          $tabla.="<td><a href='#' id='act_user' onClick='obtener$name($fila[id_usuario])'><i class='ui-icon ui-icon-refresh' style='color:black;'></i></button></td>";
          break;
        case 'Eliminar':
          $tabla.="<td><a  data-toggle='tooltip' data-original-title='Editar' href='#' onClick='eliminar$name($fila[id_usuario])'><i class='ui-icon ui-icon-trash' style='color:black;'></i></a></td>";
          break;
        default:
          break;
      }
    }

    $tabla.="</tr>";
  }
  $tabla.="</table>";
  return $tabla;
}

and the code to open the dialog is as follows:

<script>
$(function() {
var dialog, form,
  name = $( "#username_act" ),
  password = $( "#password_act" ),
  allFields = $( [] ).add( name ).add( password ),
  tips = $( ".validateTips" );

function updateTips( t ) {
  tips
    .text( t )
    .addClass( "ui-state-highlight" );
  setTimeout(function() {
    tips.removeClass( "ui-state-highlight", 1500 );
  }, 500 );
}

function checkLength( o, n, min, max ) {
  if ( o.val().length > max || o.val().length < min ) {
    o.addClass( "ui-state-error" );
    updateTips( "Length of " + n + " must be between " +
      min + " and " + max + "." );
    return false;
  } else {
    return true;
  }
}

function checkRegexp( o, regexp, n ) {
  if ( !( regexp.test( o.val() ) ) ) {
    o.addClass( "ui-state-error" );
    updateTips( n );
    return false;
  } else {
    return true;
  }
}

function actUser() {

  var valid = true;
  allFields.removeClass( "ui-state-error" );

  valid = valid && checkLength( name, "username_act", 3, 16 );
  valid = valid && checkLength( password, "password_act", 5, 16 );

  valid = valid && checkRegexp( name, /^[a-z]([0-9a-z_\s])+$/i, "Username may consist of a-z, 0-9, underscores, spaces and must begin with a letter." );
  valid = valid && checkRegexp( password, /^([0-9a-zA-Z])+$/, "Password field only allow : a-z 0-9" );

  if ( valid ) {
    if(confirm("Actualizar Usuario")){
      $.ajax({
          type: "POST",
          dataType: 'json',
          data: { 'username': $("#username_act").val(),'password': $("#password_act").val(),'rol': $("#rol_act").val()},
          url: "<?php echo site_url();?>"+"/principal/actualizarUsuario",
          success : function(data) {
            console.log(data);
            if (data == 'ok') {
              alert("Usuario actualizado correctamente");
              window.location.href = "listarUsuarios";
            }else{
              alert("Ocurrio un error al actualizar el usuario, contacte al administrador");
              window.location.href = "listarUsuarios";
            }
          }
      });
    }
    dialog.dialog( "close" );
  }
  return valid;
}

dialog = $( "#dialog-form_act" ).dialog({
  autoOpen: false,
  height: 300,
  width: 350,
  modal: true,
  buttons: {
    "Actualizar cuenta": actUser,
    Cancel: function() {
      dialog.dialog( "close" );
    }
  },
  close: function() {
    form[ 0 ].reset();
    allFields.removeClass( "ui-state-error" );
  }
});

form = dialog.find( "form" ).on( "submit", function( event ) {
  event.preventDefault();
  actUser();
});

$('#act_user').click(function(e) {
  e.preventDefault();
  dialog.dialog('open');
});

/*$( "#act_user" ).button().on( "click", function() {
  dialog.dialog( "open" );
});*/
});
</script>

I think the error is that all the buttons have the same name "# act_user" , but I do not know how to solve it.