NaN JavaScript结果

Question

我得到NaN结果。显然有些事不对。但我无法弄清楚计算中出了什么问题。继承人代码：

var totalTime = video.duration; 
var milliToHours = function (value) { 
    return value/60/60; 
} 
milliToHours (totalTime); 
// howerver it returns NaN in console 

Answer 1

video.durationvideo.duration必须在函数执行时未定义。为您的函数添加console.log(value);声明。

var totalTime; 
 
var milliToHours = function(value) { 
 
    console.log(value); 
 
    return value/60/60; 
 
} 
 
console.log(milliToHours(totalTime)); // undefined => NaN 
 
totalTime = null; 
 
console.log(milliToHours(totalTime)); // null => 0 
 
totalTime = 39856.6757; 
 
console.log(milliToHours(totalTime)); // 39856.6757 => 11.071298805555555