In certain situation, this behaviour can be quite irritating, especially if you are customising the appearance of your inputs so that that differ greatly from the standard look.

In this example, we were opting for an Apple like rounded input element using background images and a transparent input.

All appears to be fine until the input receives focus when browsing using Safari and you are presented with the following outer glow effect around the original input element.

The solution to removing this effect is a very simple one. Set the outline property of the element to none in your CSS file.

input { outline: none; }

You may want to be more specific and target a single element, but here we are setting the value for all input elements.