JsTicker -- Broken Numeric Conversion

        function JsTicker_24bit_from_color(rgb){ // Returns The Unsigned 24bit Integer Representing The Given HTML-Compliant Hexidecimal Color Code
            var i=0;
            var ret=0;

            var bpc=0; //depth as bits per channel

            switch(rgb.length){

            case 0:
                bpc=0;
                break;

            case 1:
            case 2:
            case 3:
                bpc=4;
                break;

            case 4:
            case 5:
            case 6:
                bpc=8;
                break;

            default:
                bpc=-1;
            }

            switch(bpc){

            case 4:
                for(i=2;i>=0;i--)
                    ret=ret<<8+parseInt('0x'+('0'.repeat(3)+rgb).slice(-3).substr(2-i,1).repeat(2));
                break;

            case 8:
                for(i=2;i>=0;i--)
                    ret=ret<<8+parseInt('0x'+('0'.repeat(6)+rgb).slice(-6).subtr((2-i)<<1,2));
                break;

            default:
            }

            return ret;
        }