Math.ceil

Math.ceil

Math.ceil()函数返回大于或等于一个给定数字的最小整数。

语法

Math.ceil(x)

参数

x一个数值。

返回值

大于或等于给定数字的最小整数。

描述

由于ceilMath 的静态方法,所以应该像这样使用:Math.ceil(),而不是作为你创建的 Math实例的方法。

示例

使用Math.ceil()

下例展示了 Math.ceil() 的使用:

Math.ceil(.95 // 1 Math.ceil(4 // 4 Math.ceil(7.004 // 8 Math.ceil(-0.95 // -0 Math.ceil(-4 // -4 Math.ceil(-7.004 // -7

十进制调整

// Closure (function() { /** * Decimal adjustment of a number. * * @param {String} type The type of adjustment. * @param {Number} value The number. * @param {Integer} exp The exponent (the 10 logarithm of the adjustment base). * @returns {Number} The adjusted value. */ function decimalAdjust(type, value, exp) { // If the exp is undefined or zero... if (typeof exp === 'undefined' || +exp === 0) { return Math[type](value } value = +value; exp = +exp; // If the value is not a number or the exp is not an integer... if (isNaN(value) || !(typeof exp === 'number' && exp % 1 === 0)) { return NaN; } // Shift value = value.toString().split('e' value = Math[type](+(value[0] + 'e' + (value[1] ? (+value[1] - exp) : -exp)) // Shift back value = value.toString().split('e' return +(value[0] + 'e' + (value[1] ? (+value[1] + exp) : exp) } // Decimal round if (!Math.round10) { Math.round10 = function(value, exp) { return decimalAdjust('round', value, exp }; } // Decimal floor if (!Math.floor10) { Math.floor10 = function(value, exp) { return decimalAdjust('floor', value, exp }; } // Decimal ceil if (!Math.ceil10) { Math.ceil10 = function(value, exp) { return decimalAdjust('ceil', value, exp }; } })( // Round Math.round10(55.55, -1 // 55.6 Math.round10(55.549, -1 // 55.5 Math.round10(55, 1 // 60 Math.round10(54.9, 1 // 50 Math.round10(-55.55, -1 // -55.5 Math.round10(-55.551, -1 // -55.6 Math.round10(-55, 1 // -50 Math.round10(-55.1, 1 // -60 // Floor Math.floor10(55.59, -1 // 55.5 Math.floor10(59, 1 // 50 Math.floor10(-55.51, -1 // -55.6 Math.floor10(-51, 1 // -60 // Ceil Math.ceil10(55.51, -1 // 55.6 Math.ceil10(51, 1 // 60 Math.ceil10(-55.59, -1 // -55.5 Math.ceil10(-59, 1 // -50

规范

SpecificationStatusComment
ECMAScript 1st Edition (ECMA-262)StandardInitial definition. Implemented in JavaScript 1.0.
ECMAScript 5.1 (ECMA-262)The definition of 'Math.ceil' in that specification.Standard
ECMAScript 2015 (6th Edition, ECMA-262)The definition of 'Math.ceil' in that specification.Standard
ECMAScript Latest Draft (ECMA-262)The definition of 'Math.ceil' in that specification.Living Standard

浏览器兼容性

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic Support(Yes)(Yes)(Yes)(Yes)(Yes)(Yes)

FeatureAndroidChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic Support(Yes)(Yes)(Yes)(Yes)(Yes)(Yes)(Yes)