js精确运算

var CMX = CMX || {};/**** 加**/CMX.add = function (arg1, arg2) {var r1, r2, m, c;try {r1 = arg1.toString().split(".")[1].length;}catch (e) {r1 = 0;}try {r2 = arg2.toString().split(".")[1].length;}catch (e) {r2 = 0;}c = Math.abs(r1 - r2);m = Math.pow(10, Math.max(r1, r2));if (c > 0) {var cm = Math.pow(10, c);if (r1 > r2) {arg1 = Number(arg1.toString().replace(".", ""));arg2 = Number(arg2.toString().replace(".", "")) * cm;} else {arg1 = Number(arg1.toString().replace(".", "")) * cm;arg2 = Number(arg2.toString().replace(".", ""));}} else {arg1 = Number(arg1.toString().replace(".", ""));arg2 = Number(arg2.toString().replace(".", ""));}return (arg1 + arg2) / m;};/**** 减**/CMX.sub = function (arg1, arg2) {var r1, r2, m, n;try {r1 = arg1.toString().split(".")[1].length;}catch (e) {r1 = 0;}try {r2 = arg2.toString().split(".")[1].length;}catch (e) {r2 = 0;}m = Math.pow(10, Math.max(r1, r2)); //last modify by deeka //动态控制精度长度n = (r1 >= r2) ? r1 : r2;return Number(((arg1 * m - arg2 * m) / m).toFixed(n));};/**** 乘**/CMX.mul = function (arg1, arg2) {var m = 0, s1 = arg1.toString(), s2 = arg2.toString();try {m += s1.split(".")[1].length;}catch (e) {}try {m += s2.split(".")[1].length;}catch (e) {}return Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m);};/**** 除**/CMX.div = function (arg1, arg2) {var t1 = 0, t2 = 0, r1, r2;try {t1 = arg1.toString().split(".")[1].length;}catch (e) {}try {t2 = arg2.toString().split(".")[1].length;}catch (e) {}with (Math) {r1 = Number(arg1.toString().replace(".", ""));r2 = Number(arg2.toString().replace(".", ""));return (r1 / r2) * pow(10, t2 - t1);}};