Page Load Validation

Content

Hi,

Can we do any validation when the particular page is loaded? 

I hope we can get the URL parameter value. How to do this?

Use Case:

When the particular customer clicks on the particular service in the page, it will navigate to the particular page. I have to validate whether they have certain balance in their valet, if not I have to show the some message in the screen instead of Service details.

Thanks,

Mohan