Edit in JSFiddle

<div id='container'>
    <div id='slider'></div>
</div>
<div>Progress <strong id='progress'>50</strong></div>

makeSlider();

var task = new can.Observe({progress: 50});

var progress = can.compute(function(newValue){
    if(arguments.length) { // setter
        task.attr('progress', newValue * 100)
    } else {
        return task.attr('progress') / 100
    }
})

new Slider("#slider",{
    value: progress
})

task.bind("progress",function(ev, newVal){
    $("#progress").html(newVal)
});

function makeSlider(){

    Slider = can.Control.extend({
        init: function(){
            this.updatePosition()
        },
        "draginit": function(el, ev, drag){
            drag.limit(this.element.parent());
            drag.horizontal();
        },
        "dragmove": function(el, ev, drag){
            
            var container = this.element.parent(),
                sliderOffset = el.offset().left,
                containerOffset = container.offset().left,
                sliderWidth = el.outerWidth(),
                containerWidth = container.width();
            
            containerOffset +=
                parseInt( container.css("paddingLeft") ) +
                parseInt( container.css("borderLeftWidth") )
            
            var value = ( (sliderOffset-containerOffset ) /
                         (containerWidth - sliderWidth) );
            
            
            this.options.value(value)
            
        },
        "{value} change" : "updatePosition",
        updatePosition: function(){
            var value = this.options.value(),
                container = this.element.parent(),
                containerOffset = container.offset().left,
                sliderWidth = this.element.outerWidth(),
                containerWidth = container.width();
            
            containerOffset +=
                parseInt( container.css("paddingLeft") ) +
                parseInt( container.css("borderLeftWidth") )
            
            var sliderOffset = containerOffset+
                ( 	(containerWidth - sliderWidth) * 
                 (value) )
            
            this.element.offset({
                left: sliderOffset
            })
        },
        "resize": "updatePosition"
    });
    
}