How to setup condition for Postal Address field?

Hi, im looking to add a condition based on postcode. 

So we currently only offer our services in 2 cities and would like to collect name & email address on new customer interested in using the service on our landing home page, however only allow them to continue to the booking page should their postcode belong to these two cities - if not then a notification message appear saying ' We dont currently cover this area...'  quite a standard feature used by many site like uber eats and deliveroo. 

I see it is possible to do this with the notification message in condition, and also postcode field - is there a widget that can be used that covers all postcodes in areas or is there another manual way of making this possible? 

Unfortunately there is no widget that can do this since you need to use conditions to to give an output based on user answers. 

https://www.jotform.com/help/57-Smart-Forms-Using-Conditional-Logic

I would recommend that you use something like a drop down with list of cities you deliver to since the you can not get the value for the address field hence you can not use the value option to set condition of the form.

This is the best approach I see if you need to achieve the above.

You can use a condition as shown below to determine what to display for user to continue filling the form. 

You can also add a dropown field called "Other " which will allow user to enter their Address and you can display message "We do not deliver to the address and we have added your address to our database for future deliveries" this will allow you to add list of cities you want to expand your delivery to.

So can we use postage code search/reference here?
Regards
...

As explained on my last response using the Postal Search Fields will not work in this case since you can not capture the value of this field  meaning you can not search if "Field Contains " a certain value the "Display" certain field.

In my image illustration I used a dropdown field but named it "Postal Code Search" hence reason the image displaying "Postal Code Search". My apologies for the confusion.