jQuery handle button click inside a form

i don't understand why a button inside my form can't be reached with my jQuery code.

<form action="">
    <div class="field">
        <label for='username'>Insert username</label>
        <input type="text" id="username" name="username">
    </div>

    <button type='submit' class='btn btn-lg btn-primary buttonRegister'>Register</button>
</form>

Here are my jQuery on click try codes:

$('.buttonRegister').submit(function(){  
    //action inside function
});

--------------OR----------------------

$('.buttonRegister').click(function(){  
    //action inside function
});

--------------OR----------------------

$('.buttonRegister').on("click", function(){  
    //action inside function
});

None of them worked. I'm SURE that code inside click function works because i tried to take button outside the form and it worked well.