Writing JavaScript for my plugin

Hi, whats up?

I’m writing my first plugin, and i’ve already enqueue my js file, but i’m not able to listen to the change events on my form.

I have this selectbox:

add_settings_field(
		'wcwp_select_wcwp_select_state',
		__( 'Select the state', 'woocommerce-withdrawal-point-for-brazil' ),
		'wcwp_select_state_render',
		'wcpc_pluginPage',
		'wcwp_pluginPage_section'
	);

<!-- HERE ITS THE SELECT -->
<select name='wcwp_settings_wcwp_select_state' id="wcwp_select_wcwp_select_state">
		<option value='1'>Acre</option>
		<option value='2'>Alagoas</option>
		<option value='3'>Amapá</option>
		<option value='4'>Amazonas</option>
</select>

And this is my js script:

var selectBox = document.getElementById("wcwp_select_wcwp_select_state");
selectBox.addEventListener("change", function(){
    alert("Works!");
});

But its not listening to my change event, do you know why??

Thanks a lot ??