Hindus leave their footwear like chappals, sandals and shoes outside the Hindu temple. Footwear is not allowed inside the temple and there are a couple of reasons for it.
Why shoes are not allowed in Temple?
Temples are the place that contains pure vibrations of magnetic and electric fields with positive energy. In the olden days the temples were built in such a way that the floor at the center of the temple were good conductors of positive vibrations allowing them to pass through our feet to the body. Hence it is necessary to walk bare footed while you enter the temple.
Another reason is shoes and slippers are used everywhere hence they tend to get all the impurities like dirt, germs etc. which will spoil the pure environment of the temple and is a source of negative energy.