html
<input class="knobSlider" data-readOnly="true">
<button id="testBtn">clickHere</button>
script
in doc ready,
$(".knobSlider").knob();
$("#testBtn").click(function(){
$(".knobSlider").siblings("canvas").remove();
if($(".knobSlider").attr("data-readOnly")=='true'){
$(".knobSlider").unwrap().removeAttr("data-readOnly readonly").data("kontroled","").data("readonly",false).knob();
}
else{
$(".knobSlider").unwrap().attr("data-readOnly",true).data("kontroled","").data("readonly",true).knob();
}
});
For reference you can use my jsfiddle link > http://jsfiddle.net/EG4QM/ (check this in firefox, because of some external resource load problem in chrome)