• canvas based ; no png or jpg sprites.
• touch, mouse and mousewheel, keyboard events implemented.
• downward compatible ; overloads an input element.

<inputtype="text" value="75" class="dial"><script>$(function(){$(".dial").knob();});</script>

Options are provided as attributes 'data-option':

<inputtype="text" class="dial" data-min="-50" data-max="50">

... or in the "knob()" call :

$(".dial").knob({'min':-50,'max':50});

The following options are supported :

Behaviors :

• min : min value | default=0.
• max : max value | default=100.
• step : step size | default=1.
• angleOffset : starting angle in degrees | default=0.
• angleArc : arc size in degrees | default=360.
• stopper : stop at min & max on keydown/mousewheel | default=true.
• readOnly : disable input and events | default=false.
• rotation : direction of progression | default=clockwise.

UI :

• cursor : display mode "cursor", cursor size could be changed passing a numeric value to the option, default width is used when passing boolean value "true" | default=gauge.
• thickness : gauge thickness.
• lineCap : gauge stroke endings. | default=butt, round=rounded line endings
• width : dial width.
• height : dial height.
• displayInput : default=true | false=hide input.
• displayPrevious : default=false | true=displays the previous value with transparency.
• fgColor : foreground color.
• inputColor : input value (number) color.
• font : font family.
• fontWeight : font weight.
• bgColor : background color.

<script>$(".dial").knob({'release' : function(v){/*make something*/}});</script>

• 'release' : executed on release

  Parameters :

  • value : int, current value

• 'change' : executed at each change of the value

  Parameters :

  • value : int, current value

• 'draw' : when drawing the canvas

  Context :

  • this.g : canvas context 2D (see Canvas documentation)
  • this.$ : jQuery wrapped element
  • this.o : options
  • this.i : input
  • ... console.log(this);

• 'cancel' : triggered on [esc] keydown

• 'format' : allows to format output (add unit %, ms ...)

The scope (this) of each hook function is the current Knob instance (refer to the demo code).

<inputtype="text" value="75" class="dial"><script>$(".dial").knob({'change' : function(v){console.log(v);}});</script>

<script>$('.dial').trigger('configure',{"min":10,"max":40,"fgColor":"#FF0000","skin":"tron","cursor":true});</script>

<script>$('.dial').val(27).trigger('change');</script>

Tested on Chrome, Safari, Firefox, IE>=8.0 (IE8.0 with excanvas).