CODEWITHSUNDEEP
javascriptinfinite-loop
JavaDeveloper
JavaDeveloper

Reputation: 5660

Why is my javascript code going into an infinite loop?

In the code below, whenever I click on the submit button, multiple window's open up as it it were in infinite loop. If I uncomment alert, then multiple alerts keep popping like they were in infinite loop. Why could this be happening ?

<html>
<head>

<script type = "text/javascript">
    var window;

    function moveBy() {
        //alert("-- hello ---");
        window = window.open("http://www.w3schools.com");
        window.moveBy(10, 20);
    }
</script>


</head>
<body>
<input type = "submit" value = "moveBy" onclick = "moveBy()"> </input>
</body>
</html>

Upvotes: 1

Views: 1791

Answers (4)

T3 H40
T3 H40

Reputation: 2426

Javascript does not support method overloading, so by calling window.moveBy(10, 20); you are actually basically calling moveBy() again, resulting in an infinite loop.

Calling a function from itself is called recursion. The linked post is a good read on this topic, and will guide you on where you might want it. But in your case you clearly don't.

Have a read of this article for more detail.

To prevent this from happening, you can rename your moveBy() function to myMoveBy() or better openAndMoveBy()

Upvotes: 8

taxicala
taxicala

Reputation: 21759

You are creating a recursion (function that calls itself) by calling window.moveBy inside your moveBy function without stating a break point or exit case:

function moveBy() {
    //alert("-- hello ---");
    window = window.open("http://www.w3schools.com");
    window.moveBy(10, 20); //recursion, it will call this function over and over again.
}

Maybe what you want is to use another name for your function and call the actual window.moveBy inside with predefined parameters:

function customMoveBy() {
    //alert("-- hello ---");
    window = window.open("http://www.w3schools.com");
    window.moveBy(10, 20);
}

<input type = "submit" value = "moveBy" onclick = "customMoveBy()"> </input>

Upvotes: 3

Help Needed 101
Help Needed 101

Reputation: 129

The problem is that you are calling the function moveBy inside the funtion moveBy. Whenever you execute the function you call it again and again ...

Try this:

<html>
<head>

<script type = "text/javascript">
    var window;

    function moveBy() {
        alert("-- hello ---");
        window = window.open("http://www.w3schools.com");
        //window.moveBy(10, 20);
    }
</script>


</head>
<body>
<input type = "submit" value = "moveBy" onclick = "moveBy()"> </input>
</body>
</html>

Upvotes: 1

Bogdan Savluk
Bogdan Savluk

Reputation: 6312

Because you call function moveBy from itself.

Upvotes: 7

Related Questions