javascript - 奇怪的随机值作为默认间隔处理程序参数

Question

刚刚遇到这个。它并没有真正影响任何东西，但我想知道为什么会这样。

如果我在 firefox 中运行以下代码并启用 firebug:

setInterval(function(param) 
     {
        console.log("param is %o",param)
     },500);

param 似乎被分配了一个模糊的随机值:

   param is -2
    param is -1
    param is -2
    param is 1
    param is -1
    param is 6
    param is -1
    param is 0
    param is -2
    param is 2
    param is 0
    param is 2
    param is 0
    param is 0
    param is 0
[..]
    param is 0
    param is 0
    param is 0
    param is 0
    param is 0
    param is 0
    param is 0
    param is 911
    param is 0
    param is 0
    param is 0
    param is -1

我很感激我没有将任何参数传递给 setInterval 以传递给该函数，但为什么 javascript 选择传递这个随机数？

我会期望未定义或类似的东西......

干杯

附注没有在其他浏览器测试过

Answer 1

它似乎取决于 Firefox 的 CPU 使用率。

我猜这是应该调用回调的延迟。

编辑:I was right .这是调用回调的延迟毫秒数。