javascript Hide/show div on checkbox: checked/unchecked

Question

I am trying to make a function in javascript, that will hide / show particular div in my registration form, depending on the state of my checkbox (checked or not). Here is

Answer 1

You should write it like this :

function doruc() {
var elem = document.getElementById('powermail_fieldwrap_331');
    if (document.getElementById ('powermail_field_doruovaciaadresa2_1').checked) {
    elem.style.display='block';
    } else {elem.style.display='none';}}

and regarding your second question, you can either write in the div tag style="display:none" or you can do as you said (add a class for the element).