The normal way of reading a form value is:

var city= $("[name='city']").val(); //using the element's name

or

var city= $("#city").val(); //using the element's ID

Question: What if you had several checkboxes e.g.
<input type='checkbox' name='cities[]' value='Kisumu' />
<input type='checkbox' name='cities[]' value='Mombasa' />
<input type='checkbox' name='cities[]' value='Nairobi' />

And you want to find out which one's the user clicked on, assuming that the user can choose more than one.

var city= $("[name='cities[]']").val(); //is not working