Question

In my javascript code i have the following:

function foo(param1) {
    setInterval( bar(param1), 3000 );
}

function bar(msg) {
    alert(msg);
}

function set() {
    foo('hello');
}

And on page load i call set(), it gives the alert message only once. Why it does not work as i would expect.? I think the problem is with the parameter that i am passing the foo() function, but what it is exactly, i am not able to figure out.

If the problem is with the parameter, what can be an alternate way to achieve the desired result.?

Thanks.

Answer 1

You need to pass a function to setInterval, you are executing a function and passing it’s return value (undefined since the function executed does not have a return value).

Try using an anonymous function instead:

function foo(param1) {
    setInterval(function () {
        bar(param1);
    }, 3000);
}

function bar(msg) {
    alert(msg);
}

param1 never changes here, so there is no need for anything more complicated. Here’s a working example.