Why getComputedStyle contain visibility as visible?

Question

Why getComputedStyle returns element visibility as visible even if you never set visibility to be hidden or visible.

Example: getComputedStyle($('#block1')[0],null).visibility; --- "visible"

and at the same time: $('#block1')[0].style.visibility --- ""

Answer 1

The default for most existing DOM elements that require rendering to the document is visibility: visible. These properties only apply themselves once the element is rendered and are computed without being applied to the style object of a DOM element. The getComputedStyle method is there to pick up these rendered properties which are either from the browser's default configuration or from the stylesheet.