The features a cartoon pet that morphs and changes shape while the user answers a series of questions.
Once all the questions are answered, the most suitable pet for their lifestyle is revealed.
The questions are based on a four-step "PETS" formula, which covers the key elements that need to be considered when choosing a pet.
These elements include the Place in which the owner lives, the amount of Exercise that the owner can provide the pet, the Time they can devote to it, and the amount they can afford to Spend on expenses over the pet's lifetime.
PDSA's digital agency Cheeze worked on the media creative, planning and buying, while Cheeze's sister digital agency Hyperlaunch created the widget.
The widget is part of the charity's 'Long Live Pets' campaign, which promotes the health and happiness of pets by encouraging responsible ownership.
It is supported by a Facebook fan page, banner and digital engagement ads on , plus banner ads on and Adviva.
Emma Perkins, PDSA product manager, e-commerce, said: "If people choose the wrong pet for their lifestyle, the animal is likely to suffer.
"By providing key advice on choosing the right pet and caring for them wrapped up in a fun, easy-to-use tool -- the first of its kind -- we'll be able to build upon our responsible ownership messages ensuring the health and happiness of all pets."
Nathan Cook, account director at Cheeze, said: "The widget creates a fun, yet practical, guide to taking a responsible approach to [choosing a pet]."