!true == false
!!true == true这句话是定义了一个对象,他实际等同于:
var Tree = new Object();
Tree.version = "1.0.0.0";
Tree.Browser = {};。这样的
!!true == true这句话是定义了一个对象,他实际等同于:
var Tree = new Object();
Tree.version = "1.0.0.0";
Tree.Browser = {};。这样的
var a;
a = !!a;
alert(typeof a); //alert boolean将任意变量转换为boolean变量