关于小数转换成度分秒的问题

function change(jwd){
            var str = jwd;
            var i = str.indexOf('.');            
            var strDu = str.substring(0,i);      // 取0到小数点间的子串
            var strFen = "0" + str.substring(i);  // 得到字符串 0.xxxxxxxx
            var strMiao = "";            
            var Fen = strFen * 60;        
            i = Fen.indexOf('.');   
                strFen = Fen.substring(0,i);   
            strMiao = "0" + Fen.substring(i);
            var Miao = strMiao * 60;   
            i = Miao.indexOf('.');
            Miao = Miao.substring(0,i);   
            var dfm = strDu + "°" + strFen+ "\'" + Miao+ "\"";
            return dfm;
        }