非法的退货声明错误

Question

What is wrong with my return statement?

var creditCheck = function (income) {
    var val = income;
    return val;
};
if (creditCheck > 100) {
    return "You earn a lot of money! You qualify for a credit card.";
} else {
    return "Alas, you do not qualify for a credit card. Capitalism is cruel like that.";
}
console.log(creditCheck(75));

Answer 1

Your return statements are outside of any function. You can only use return within a function.

(You're also comparing a function with an integer, in if (creditCheck > 100) - did you mean to call the function there?)

Answer 2

I have provided some clarification to your question below. Hope it helps.

var income = 50; // Firstly, you need to declare income which I have set to 50 in this case//

//You then need to declare creditCheck as a function of income. Note that, return only works within a function. To print to the console outside of a function, make use of console.log()//

var creditCheck = function (income) {
  if (income > 100) {
    return "You earn a lot of money! You qualify for a credit card.";} 
    else {
        return "Alas, you do not qualify for a credit card. Capitalism is cruel like that.";
    }
};

creditCheck(income); //You can execute the function by calling it.//

//The text below shows what was printed to the console upon executing the function//

"Alas, you do not qualify for a credit card. Capitalism is cruel like that."

Answer 3

Re-indenting and simplifying your code reveals:

var creditCheck = function(income) {
    return income; // essentially a no-op
};
if( creditCheck > 100) { // if a function is greater than a number?
    return "You earn a lot...";
    // is this code in a function? Otherwise it's an invalid return!
}
// else is unnecessary, due to `return` above.
return "Alas, you lack basic JavaScript knowledge...";
// console.log is never reached due to `return`.

See comments - there's a lot wrong!

Answer 4

if (creditCheck > 100) {
    return "You earn a lot of money! You qualify for a credit card.";
} else {
    return "Alas, you do not qualify for a credit card. Capitalism is cruel like that.";
}

both of these returns are invalid because they are not within a function.

(creditCheck > 100) is invalide because credicheck is a function and needs to be supplied with a variable to return anything

var creditCheck = function (income) {
    return income;
};
if (creditCheck(50) > 100) {
    console.log("You earn a lot of money! You qualify for a credit card.");
} else {
    console.log("Alas, you do not qualify for a credit card. Capitalism is cruel like that.");
}

would add Alas, you do not qualify for a credit card. Capitalism is cruel like that. to the console log

Please download http://www.helpmesh.net/s/JavaScript/ javascript.chm to get basic syntax for javascript and you will save yourself a lot of time. The kind of problems, syntax, you are having is not what stackexchange was created for.