Edit in JSFiddle 

$(document).ready(function() {
  $(".address_field").each(function(index){  
    var widget = new AddressFinder.Widget(this, "WR3NUKVGC4Q97FPHBJXL");
  });
});

External resources loaded into this fiddle:

<label for="search_field">Address</label>
<input type='text' class='address_field' />
body {
    padding: 5px;
}

label {
    font-weight: bold;
}

input[type=text] {
    width: 20em
}

p {
    margin: 1em 0 0;
}