js计算中分母为0

1.任何数值除以0都会导致错误(数学规定)而终止程序执行,但是在 JavaScript 中，会返回出NaN，不影响后面程序

2.比0大的数除以0，会得到无穷大 | 在 js用 Infinity 来显示.

js中0或者可以转换为0的值除以0得到的结果都是NaN,非0或者可以转换为非0的值除以0得到的结果都是Infinity

例:

0/0  NaN   ---
false/0  NaN
'0'/0  NaN
'false'/0  NaN
null/0  NaN
'null'/0  NaN
undefined/0  NaN
'undefined'/0  NaN
'true'/0  NaN
NaN/0  NaN
[]/0 NaN
'{}'/0 NaN
'{a:1}'/0 NaN
{}/0   报错'Uncaught SyntaxError: Invalid regular expression: missing /'

1/0  Infinity
true/0  Infinity
[1]/0 Infinity
1/0  Infinity
{a:1}/0 Uncaught SyntaxError: Invalid regular expression: missing /

例题:
var num1 =1,num2=2,num3=3;
var course = (num1>num2) || (num2<num3); //true
var result = course /0; //Infinity
if(result==result){
    console.log(result/4000+'4')
}else{
    console.log(!result*4000+'4')
}
输出:Infinity4

www.cnblogs.com/peakleo/p/6…