jquery - Wordpress data attribute security right value -

i have client side html form send ajax server data. problem can change input value (right click , "inspect element" chrome) , data server side can wrong.

example:
1. html form
2. send data server ajax
3. php data client side

<form> <input type="hidden" name="user_id" value="<?php echo $user_id; ?>"> <input id="send" type="submit" value="send"> </form>   $('#send').on('click', function(){   var user_id = jquery('input[name="user_id"]').val();     jquery.ajax({           type: 'post',           url: 'wp-admin/admin-ajax.php',           data:{           'action':'my_form',           'user_id': user_id,           },            success:function(data){             console.log(data);             }    }); });  function my_form(){     $user_id = $_request['user_id']; } 

anybody can change hidden "user_id" field , set value 123 or 4856 example. data in $user_id server side can wrong. can sure data client side right ?

p.s: sorry english

if logged in user id don't trust on client side values instead use following in php code

$current_user = wp_get_current_user(); $userid = $current_user->id; 

https://codex.wordpress.org/function_reference/wp_get_current_user