title: allow only letters and spaces validate jquery
body: <p>I have this code: </p>
  
  <pre><code>$(document).ready(function(){
          jQuery.validator.addMethod("lettersonly", function(value, element) {
              return this.optional(element) || /^[a-z]+$/i.test(value);
          }, "Only alphabetical characters"); 
  </code></pre>
  
  <p>But if I insert a double name like "Mary Jane" the space creates a problem. how can i allow spaces too in my rule?</p>