JS 浮点计算 精度缺失
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title> JS 浮点计算精度问题 </title> </head> <body> <script type="text/javascript"><!-- function accDiv(arg1, arg2) { var t1 = 0, t2 = 0, t3 = 0, r1, r2; try { t1 = arg1.toString().split(".")[1].length } catch (e) { } try { t2 = arg2.toString().split(".")[1].length } catch (e) { } r1 = Number(arg1.toString().replace(".", "")) r2 = Number(arg2.toString().replace(".", "")) if (r2 == 0) return 0; var result = String(r1 / r2); try { t3 = result.toString().split(".")[1].length } catch (e) { } var index = t2 - t1 - t3; if (index < 0) { result = result.replace(".", ""); while (result.length <= Math.abs(index)) { result = '0' + result; } var start = result.substring(0, result.length + index); var end = result.substring(result.length + index, result.length); result = start + '.' + end; return Number(result); } else if (index > 0) { result = result.replace(".", ""); while (result.length <= Math.abs(index)) { result += '0'; } return Number(result); } else return Number(result.replace(".", "")); } //给Number类型增加一个div方法，调用起来更加方便。 Number.prototype.div = function (arg) { /// <summary> /// 除法 /// </summary> return accDiv(this, arg); } function accMul(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) } Number.prototype.mul = function (arg) { /// <summary> /// 乘法 /// </summary> return accMul(arg, this); } function accAdd(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 } Number.prototype.add = function (arg) { /// <summary> /// 加法 /// </summary> return accAdd(arg, this); } // 除法，两种写法，都可以，其他一样alert(accDiv(2.1,10)); alert(2.1.div(10));// 乘法alert(accMul(2.1,0.01));//--></script> </body></html>?