i'm using knob jQuery to create an interactive knob, that, allowing sunstantial to see how much energy is consuming its power grid
this is the code that generate the knob
$(function(){
      $(".dial").knob({
            'min':0,
            'max':5000,
            'readOnly': true,
            'width': 120,
            'height': 120,
            'float' : 'left',
            'fgColor': '#b9e672',
            'dynamicDraw': true,
            'thickness': 0.2,
            'tickColorizeValues': true,
            'skin':'tron'
        }) 
      // body...
    });
and this is the input:
<input id='knobinput' type='text' value='75' class='dial'>
I would like to make sure that if the knob is less than 1500 is green, if between 1500 and 3000 yellow and red if above 3000.
how can I do this?
thanks