Need help using valid_url rule reference

Hey Guys,

I am trying to use the valid_url rule in CodeIgniter and it doesn't seem to be working.

When I submit the form by just typing it "test" it doesn't display any kind of validation error. I'm not sure what is wrong here.

If anyone can help me out I would really appreciate it. Thanks!

PHP Code:

private  function validateForm(){


    $this->form_validation->set_rules("proj_url","project URL", "required|valid_url",[
        "required" => "Please enter a project url",
        "valid_url" => "Please enter the %s in the correct url format (www.myproject.com)"
    ]);



}