its dont drawing anything. please help

var color = $(".seleted").css("background-color");
var $canvas = $("canvas");
var context = $canvas[0].getContext("2d");
var lastEvent;
var mouseDown = false;

$(".controls").on("click", "li", function(){

    $(this).siblings().removeClass("selected");

     $(this).addClass("selected");

    color = $(this).css("background-color");

});

$("#revealColorSelect").click(function(){
    changeColor();
    $("#colorSelect").toggle();    
});

function changeColor() {
   var r = $("#red").val();
    var g = $("#green").val();
    var b = $("#blue").val();
    $("#newColor").css("background-color", "rgb(" + r +"," + g + ", " + b +")" );

}

$("input[type=range]").change(changeColor);


$("#addNewColor").click(function(){
    var $newColor = $("<li></li>");
    $newColor.css("background-color", $("#newColor").css("background-color"));
    $(".controls ul").append($newColor);

    $newColor.click();

})

$canvas.mousedown(function(e){
    lastEvent = e;
    mouseDown = true;

}).mousemove(function(e){

    if(mouseDown) {
    context.beginPath();
    context.moveTo(lastEvent.OffsetX, lastEvent.OffsetY);
    context.lineTo(e.OffsetX, e.OffsetY);
    context.strokeStyle = color;
    context.stroke();

    lastEvent = e;
    }
}).mouseup(function(){
    mouseDown = false;


});