'null's number value acting differently
'null's number value acting differently
在Ecma-262中,它说null的数值是+0。所以当我这样做的时候:
var a = null; //so now a = 0
var b = 0;
var c = 1;
alert(a * c); //shows '0' as expected
alert(a < c); //shows 'true' as expected
alert(a > c); //shows 'false' as expected
alert(a === b); //shows 'false'
alert(a == b); //shows 'false' - why ?
我知道从Ecma-262 javascript对待+0和-0相同。那么为什么显示false呢?
当在算术表达式中使用时,null
与+0
等效,但它实际上没有值 +0
。null
是null
,如果你将它与不是null
的东西进行比较,那么它将是假的。