jQuery UI #6059
http://bugs.jqueryui.com/ticket/6059
HTML
<script src="http://code.jquery.com/jquery-1.8.2.js"></script>
<link href="http://code.jquery.com/ui/1.9.0/themes/base/jquery-ui.css" rel="stylesheet" />
<script src="http://code.jquery.com/ui/1.9.0/jquery-ui.js"></script>
<div id="buttons">
<button>On</button>
</div>
CSS
.ui-state-disabled .ui-icon {
filter:Alpha(Opacity=90);
}
JavaScript
$('#buttons').button({
icons: {
primary: 'ui-icon-gear'
},
disabled: true
});