In Javascript, does console.log on an object call toString?

问题

Array.prototype.toString = function(){
    return "testing";
}

a1 = [1,2,3];

console.log(a1); // returns [1,2,3]
console.log(a1.toString()); // returns "testing"

why is that? How does the first log print out values? I thought it used the toString method?

回答1:

For Firefox(both Firebug and Dev Web Console), Chrome: No

For IE: Yes

来源：https://stackoverflow.com/questions/13244308/in-javascript-does-console-log-on-an-object-call-tostring