Computed vs Cascaded Style

Computed vs Cascaded Style

function getStyle(el, prop) {    if (document.defaultView && document.defaultView.getComputedStyle) {      return document.defaultView.getComputedStyle(el, null)[prop];    } else if (el.currentStyle) {      return el.currentStyle[prop];    } else {      return el.style[prop];    }}

So what is wrong with this you might ask? Lets add some background and then
we can get back to that question. …
All browsers except IE has a way to get the computed style. The way to do
this is to use document.defaultView.getComputedStyle. Only IE has a way to get
the cascaded style. This is done using element.currentStyle.