本次函数调用时传入函数的实参数量.
arguments.length
arguments.length表示的是实际上向函数传入了多少个参数,这个数字可以比形参数量大,也可以比形参数量小(形参数量的值可以通过Function.length获取到).
arguments.length
这个例中,我们定义了一个可以相加任意个数字的函数.
function adder(base, /*, n2, ... */) {
base = Number(base);
for (var i = 0; i < arguments.length; i++) {
base += Number(arguments[i]);
}
return base;
}
Specification | Status | Comment |
---|---|---|
ECMAScript 1st Edition (ECMA-262) | Standard | Initial definition. Implemented in JavaScript 1.1 |
ECMAScript 5.1 (ECMA-262) Arguments Object |
Standard | |
ECMAScript 2015 (6th Edition, ECMA-262) Arguments Exotic Objects |
Standard | |
ECMAScript Latest Draft (ECMA-262) Arguments Exotic Objects |
Draft |
Desktop | Mobile | Server | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
length | Chrome Full support Yes | Edge Full support Yes | Firefox Full support 1 | IE Full support Yes | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Edge Mobile Full support Yes | Firefox Android Full support 4 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes | nodejs Full support Yes |