Depends on how you're delivering your ads and other factors, and there are a lot of specifics and different ways to do it based on what you want to achieve, but the big answer is you're going to require a developer / web designer who can write some Javascript in order to do this.
Questions
Depends on how you're delivering your ads and other factors, and there are a lot of specifics and different ways to do it based on what you want to achieve, but the big answer is you're going to require a developer / web designer who can write some Javascript in order to do this.