function z(){
var arr = [];
var a = function(){ this.toString = function(){ return 9; };};
arr[0] = new a();
console.log(""+arr[0]); //9
console.log(arr[0]); //a {toString: ƒ}
};
var w = new z();
为何前面有个""+ 就把里面的方法给执行了。两个console.log()的结果不应该是一样的吗