In the Decoding jQuery series, we will break down every single method in jQuery, to study the beauty of the framework, as an appreciation to the collective/creative geniuses behind it.
jQuery.isWindow()
jQuery has a jQuery.isWindow() method, this is used in a number of places in jQuery itself to determine if it’s operating against a browser window (such as the current window or an iframe).
<!doctype html>
<html>
<head>
<script src="http://code.jquery.com/jquery-latest.js"></script>
</head>
<body>
Is 'window' a window? <b></b>
<script>$("b").append( "" + $.isWindow(window) );</script>
</body>
</html>So how does the actual source look like? It looks like below:
// A crude way of determining if an object is a window isWindow: function( obj ) { return obj && typeof obj === "object" && "setInterval" in obj; }
Here is how it works:
1. it detects if there is an object being returned
2. it detects if the object type is object
3. it sees if setInterval is a method of the object, setInterval is part of window.setInterval, it’s a method that’s only available in window object.
Reference:
http://api.jquery.com/jQuery.isWindow/
https://github.com/jquery/jquery/blob/master/src/core.js#L480
https://developer.mozilla.org/En/Window.setInterval
