On 1/28/2011 3:33 PM, Ryosuke Niwa wrote:
On Wed, Jan 26, 2011 at 10:23 PM, Brett Zamir<bret...@yahoo.com> wrote:
I'll give a more concrete example, but I did state the problem: separation
of concerns, and the data I want, getting a CSS property for a given
selector.
For example, we want the designer guy to be able to freely change the
colors in the stylesheet for indicating say a successful transition (green),
an error (red), or waiting (yellow) for an Ajax request. The JavaScript girl
does not want to have to change her code every time the designer has a new
whim about making the error color a darker or lighter red, and the designer
is afraid of getting balled out for altering her code improperly. So the
JavaScript girl queries the ".error" class for the "background-color"
property to get whatever the current error color is and then indicates to an
animation script that "darkred" should be the final background color of the
button after the transition. The retrieval might look something like:
document.getCSSPropertyValue(".error", "background-color"); // 'darkred'
While the JavaScript would choose the intermediate RGB steps to get there
in the fashion desired by the developer.
Yes, there are CSS transitions, or maybe SVG, but this is for cases where
you want control tied to JavaScript.
It sounds like all you want to do is:
function getColor(className) {
var dummy = document.createElement('div');
dummy.className = className;
document.body.appendChild(dummy);
var color = dummy.style.backgroundColor;
document.body.removeChild(dummy);
return color;
}
Yes, mostly that would work too, yes, but again with some greater
ambiguity if someone say styled, "body > .myClass" as opposed to ".myClass".
Or, to piggy-back on what Boris suggested:
function getColor(className) {
var dummy = document.createElement('div');
dummy.className = className;
return getComputedStyle(dummy, null).getPropertyValue('color');
}
While this is not a frequent use case, I'll admit, this need to ensure
separation of concerns is, in my view, something fundamental enough to
call for a built-in method, despite the fact that there are a number of
ways this can be done.
Brett
