Javascript, adding an removing CSS on button press (shutter reloaded)

Javascript, adding an removing CSS on button press (shutter reloaded)

I've tried editing the Shutter Reloaded script to simply add in a bit of
CSS when the resize button is pressed, but I can't get it to work as my
javascript knowledge is terrible. This is what I've tied doing:
Resize : function(ln) {
if ( this.resizing ) return;
if ( ! this.I('shShutter') ) return;
var W = this.I('shWrap');
if ( W ) W.style.visibility = 'hidden';
window.setTimeout(function(){shutterReloaded.resizing = null},500);
window.setTimeout(new Function('shutterReloaded.VP =
null;shutterReloaded.Make("'+ln+'");'),100);
this.resizing = true;
document.getElementById("colour").style.property=display="none";
},
I'm wanting to add: display: "none"; to the div #colour, but yeah can't
seem to get it to work.
The page its on is this: Link
It probably helps to have the rest of the code too:
shutter.js
Any idea's guys?