这是使用带有函数的对象的正确方法吗？

Question

Is this the correct way to create an Object and place a function inside of it? Every example I come across uses code that is to simple to understand and to use effectively in an actual situation. So I'm trying to figure this out by doing.

function calc() //creating an empty object named calc
{
}

var calc = new calc(); //creating a new instance of the calc object

calc.arithmetic = function maths (input) 
{
    var str = input;
    var a=str.substr(1,1); 
    var b=str.substr(2,1);
    var c=str.substr(3,1);

    if(b == "+")
    {
        answerNumber = a + c;
    }
    else if(b == "-")
    {
        answerNumber = a + c;
    }
    else if(b == "*")
    {
        answerNumber = a * c;
    }
    else if(b == "/")
    {
        answerNumber = a / c;
    }
}
document.getElementById("input").value=answerNumber;




document.write(calc.arithmetic(input))  //calling the method in the context of the object.

Answer 1

You're overwriting calc with a fresh object containing only myArithmetic here.

You should be doing calc.myArithmetic=function(){}; instead - this adds a new property with your function as value, which is probably what you want.

Answer 2

我将看看Douglas Crockford网站（http://www.crockford.com/javascript/private.html）。