Javascript: A simple way when validating forms to ensure at least one checkbox is checked

Check so at least one checkbox on your form is checked before it's allowed to submit:  

How to add more form fields and data to a serialized AJAX form in JQuery

In a jQuery form post, here is how you add more data to the serialized form data.  This is useful if you find yourself needing to pass some extra data along with the AJAX post.  This is a barebones example of a blind AJAX post to a form handler script called "form_handler.php". I find jQuery's…

Get date of last day of current month for special processing like for credit card expiration dates

In case you ever need to manually validate those pesky multi-field credit card date fields, you know "Month" and "Year" and you want to make sure the expiration is never set prior to the current month for obvious reasons like the credit card would get declined, you need to have the browser client side figure…