TypeError：rgb未定义

Question

我的代码很难将rgb背景颜色转换为Hex 它说“TypeError：rgb未定义”。我只是不明白。 我使用jquery 1.9.1 任何的想法？最好

  $(document).ready(function(){

                $(".main").onepage_scroll({
                    sectionContainer: "section"
                });

                function rgb2hex(rgb) {
                    var hexDigits = ["0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"];
                    rgb = rgb.match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/);

                    function hex(x) {
                        return isNaN(x) ? "00" : hexDigits[(x - x % 16) / 16] + hexDigits[x % 16];
                    }
                        return "#" + hex(rgb[1]) + hex(rgb[2]) + hex(rgb[3]);
                    }

                $('.background').each(function(i){

                    var id = '#projet' +i;
                    var idColor ='#paragraphe' +i;
                    var color = $(idColor).css('background-color');
                    var hexa = rgb2hex(color);

                    $(id).bind('inview', function(event, visible){
                        if(visible){ 
                            $('body').stop().animate({ 
                                backgroundColor: 'hexa'
                            }, 1000);
                            console.log(idColor);
                            console.log(hexa);
                        } return false;
                    });    

                });
            });