How to overload constructor of an Object in JS (Javascript)?

Question

Can I do something like?:

function User(form) {
    this._username = form.username.value;
    this._password = form.password.value;
    this._surname = form.surn         


        

Answer 1

Overload the constructor or any other Javascript function by counting the number of arguments:

function FooString()
{   if(arguments.length>0)
    {   this.str=arguments[0];
        return;
    }
    this.str="";
}

var s1=new FooString;
var s2=new FooString("hello world");

You can also set default arguments by detecting how many arguments are missing.