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其他参考手册

CSSStyleDeclaration JS 类型转换


JavaScript round() 方法


实例

将数字四舍五入到最接近的整数:

Math.round(2.5);
亲自试一试 »

页面下方有更多实例。


定义和用法

round() 方法将数字四舍五入到最接近的整数。

注释:2.49 将向下舍入 (2),而 2.5 将向上舍入 (3)。

说明

对于 0.5,该方法将进行上舍入。

例如,3.5 将舍入为 4,而 -3.5 将舍入为 -3。


浏览器支持

方法
round() Yes Yes Yes Yes Yes

语法

Math.round(x)

参数值

参数 描述
x 必需。要四舍五入的数字。


技术细节

返回值: 数值,表示最接近的整数。
JavaScript 版本: ECMAScript 1

更多实例

实例

将不同的数字四舍五入到最接近的整数:

var a = Math.round(2.60);
var b = Math.round(2.50);
var c = Math.round(2.49);
var d = Math.round(-2.60);
var e = Math.round(-2.50);
var f = Math.round(-2.49);
亲自试一试 »