JavaScript | Math.round()方法 (JavaScript | Math.round() Method)
Math.round() is a function in math library of JavaScript that is used to round the given number floating-point number to the nearest integer value.
Math.round()是JavaScript数学库中的函数，用于将给定数字浮点数舍入到最接近的整数值。
It works in a way that if the fraction part is smaller than 0.5 it rounds down (nearest integer small than it) and if the fraction part is greater than 0.5 it rounds up (nearest integer greater than it).
它的工作方式是，如果小数部分小于0.5，则四舍五入(最接近的整数小于它)，如果小数部分大于0.5，则四舍五入(最近的整数大于它)。
Syntax:
句法：
Math.round(value);
Parameter(s):
参数：
value – represent the value to be rounded.
值 –表示要四舍五入的值。
Return value:
返回值：
The return type of this method is number, it returns the value which is nearest integer of the given value.
该方法的返回类型为number ，它返回的值是给定值的最接近整数。
Values accepted: Integer, floating-point, numeric string.
接受的值：整数，浮点数，数字字符串。
Invalid Values: non-numeric string, empty variable, empty array all will return NaN (Not a Number).
无效值：非数字字符串，空变量，空数组都将返回NaN(非数字)。
Browser support: Chrome, Internet asinlorer, Mozilla, Safari, Opera mini.
浏览器支持： Chrome，Internet代理，Mozilla，Safari，Opera mini。
Example 1: Valid values
示例1：有效值
console.log(Math.round(5.49999));
console.log(Math.round(-3.500121));
console.log(Math.round(0.990));
console.log(Math.round("-12.65"));
Output
输出量
5
-3
1
-11
Example 2: Invalid values
示例2：无效值
console.log(Math.round("Javascript"));
Output
输出量
NaN
翻译自: https://www.includehelp.com/code-snippets/math-round-method-with-example-in-javascript.aspx
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