Console.log返回错误的答案

Question

I'm new to JS, it's my first logical programming language. For some reason no matter what my income and loanAmount is the else console.log is returned. What can't I get the "Approved" message to show?

function LoanApp(personName, income, loanAmount){
    this.personName = personName;
    this.income = income;
    this.loanAmount = loanAmount;

    var bankBranch = "New York";
    var approvalStatus = "invalid";

    this.submit = function (income, loanAmount){
        if (income / loanAmount >= 2) {
            approvalStatus = "Approved";
            console.log("Congrats you're approved for " + this.loanAmount + ".")
        } else {
            approvalStatus = "On Review";
            console.log("Your application needs further review.")
        };
    };
};

var tony = new LoanApp("Tony"5000,1000);
tony.submit();  //returns else console.log but should be "Congrats"

Answer 1

Your submit function is defined as function (income, loanAmount) . Since you don't pass anything to the function, both are set to undefined, and undefined / undefined >= 2 evaluates to false .

All you have to do to fix this is:

1. Remove the parameters from the function declaration.

2. Replace all occurrences of income with this.income (and same with loanAmount ) in the function, so it knows what scope to look for them in.

Answer 2

All you have to do is append the keyword this to the variables in your if then statement that determines if the value is >= 2. This will give the function access to the variables, otherwise it can't access them because they are out of the scope of the function.

Javascript: jsfiddle example - http://jsfiddle.net/larryjoelane/zrkdyq9c/6/

function LoanApp(personName, income, loanAmount){
    this.personName = personName;
    this.income = income;
    this.loanAmount = loanAmount;

    var bankBranch = "New York";
    var approvalStatus = "invalid";

    this.submit = function (income, loanAmount){
        if ((this.income / this.loanAmount) >= 2) {  //<-----change that fixes code



            approvalStatus = "Approved";
            console.log("Congrats you're approved for " + this.loanAmount + ".")
        } else {


            approvalStatus = "On Review";
            console.log("Your application needs further review.")
        };
    };
};

var tony = new LoanApp("Tony",5000,1000);
tony.submit();  //returns else console.log but should be "Congrats"