# Math.max()

`Math.max()` 函式會回傳零或多個數字中的最大值。

## 語法

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

### Parameters

`value1, value2, ...`
Numbers.

### Return value

The largest of the given numbers. If at least one of the arguments cannot be converted to a number, `NaN` is returned.

## 說明

Because `max()` is a static method of `Math`, you always use it as `Math.max()`, rather than as a method of a `Math` object you created (`Math` is not a constructor).

If no arguments are given, the result is -`Infinity`.

If at least one of arguments cannot be converted to a number, the result is `NaN`.

## 範例

### 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.

## 規範

Specification Status Comment
ECMAScript 1st Edition (ECMA-262) Standard Initial definition. Implemented in JavaScript 1.0.
ECMAScript 5.1 (ECMA-262)
The definition of 'Math.max' in that specification.
Standard
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Math.max' in that specification.
Standard
ECMAScript Latest Draft (ECMA-262)
The definition of 'Math.max' in that specification.
Draft

## 瀏覽器相容性

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