Email Fields
Form Element
form.elements.my_email_field = {
  title:'Email Address',
  type:'email',
  default_value:'foo@bar.com'
};
Render Array
var content = {
  my_email_field:{
    theme:'email',
    attributes:{
      value:'foo@bar.com'
    }
  }
};
theme('email', ...)
var html = theme('email', {
  attributes:{
    value:'foo@bar.com'
  }
});