Mask.js makes it easy to add a opacity layer to DOM Element. Especially for the annoying IE bug.
a Mask object will be automatically created and attached to window. It has 3 Public APIs:
// debug: once the `debug` method is called, the layer's value
// of opacity will set to 0.6
// NOTE: make sure the method is called before `set`
Mask.debug()
// create mask for dom element(s)
Mask.set(element1, element2, ... elementN);
// remove the mask over the dom element(s)
Mask.remove(element1, element2, ... elementN);Licensed under MIT. (c) Sofish Lin