Drupal 7 hook menu validating argument from url
Before getting into any of the technical aspects, I would suggest you to try and understand the ‘How & why? This will help you concrete you knowledge about any form of technology.
So let’s begin with a functionality instance of Drupal called “validation”.
I have started blogging again after a brief break to share my knowledge of Drupal.The plugin takes a term ID from the URL and passes it to Views.We'll override the plugin so that it takes a string from the URL (slug), and then looks up the associated term ID.As of now there are a list of functions available to execute basic validation over form.Validate function using _form_validate from drupal API We can add custom handler to validate the data entered into the field. It is simply the name of the form followed by '_validate'.
We implement this hook to tell Drupal to include our custom argument plugin which we will create in the next step.