Math.max() - JavaScript 编辑

The Math.max() function returns the largest of the zero or more numbers given as input parameters.

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The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

Math.max([value1[, value2[, ...]]])

Parameters

value1, value2, ...

Numbers.

Return value

The largest of the given numbers. If any of the arguments are NaN or cannot be converted to a number, NaN is returned.

Description

Because Math is not a constructor, max() is a static method of Math (You always use it as Math.max(), rather than as a method of an instanced Math object).

-Infinity is the initial comparant because it is smaller than all other numbers, so that's why when no arguments are given, -Infinity is returned.

If any of the arguments are NaN or cannot be converted to a number, the result is NaN.

Examples

Using Math.max()

Math.max(10, 20);   //  20
Math.max(-10, -20); // -10
Math.max(-10, 20);  //  20

Getting the maximum element of an array

Array.reduce() can be used to find the maximum element in a numeric array, by comparing each value:

var arr = [1,2,3];
var max = arr.reduce(function(a, b) {
    return Math.max(a, b);
});

The following function uses Function.prototype.apply() to get the maximum of an array. getMaxOfArray([1, 2, 3]) is equivalent to Math.max(1, 2, 3), but you can use getMaxOfArray() on programmatically constructed arrays. This should only be used for arrays with relatively few elements.

function getMaxOfArray(numArray) {
  return Math.max.apply(null, numArray);
}

The new spread operator is a shorter way of writing the apply solution to get the maximum of an array:

var arr = [1, 2, 3];
var max = Math.max(...arr);

However, both spread (...) and apply will either fail or return the wrong result if the array has too many elements, because they try to pass the array elements as function parameters. See Using apply and built-in functions for more details. The reduce solution does not have this problem.

Specifications

Specification
ECMAScript (ECMA-262) The definition of 'Math.max' in that specification.

Browser compatibility

BCD tables only load in the browser

See also

• Math.min()