More simple:
//javascript code
var color = $('#my_element').css('backgroundColor');
var rgb = /rgb\((\d+), (\d+), (\d+)\)/.exec(color);
var r = rgb[1],
g = rgb[2],
b = rgb[3];
console.log('Red :' + r);
console.log('Green:' + g);
console.log('Blue :' + b);