Remember the last time you were in a hotel waiting for an elevator? Someone waiting for the elevator probably pressed the call button more than once. And if the elevator didn't arrive immediately, the button was probably pressed again and again.

I guess this is natural behavior. If the elevator doesn't respond right away, press the button again - maybe it didn't get the message the first time.

This same kind of behavior exists on the web - if a visitor clicks a web page link and nothing happens, the visitor will probably click the link again - just to make sure they really clicked it the first time.

In most cases, this won't cause a problem. But if the link being clicked is a button on a order form connected to a credit card processing system, each time the button is clicked, a new credit card charge could be initiated - sometimes resulting in customers being charged multiple times for a single purchase.

There is an easy way to reduce the chance of this happening. Simply add the following message below the 'order' button on your order form:

"NOTE: It can take up to a minute to process the credit card information and obtain approval. Please do not press the submit button multiple times - doing so could cause double billing."

It costs you nothing to add this message to your order page, but doing so provides immediate benefits to both you and your customers.