Window topProperty
Window Object
Definition and Usage
The top property returns the topmost browser window of the current window.
Syntax
window.top
Browser Support
All major browsers support the top property.
Example
Example
When the "Check window" button is clicked, check() is called and checks the state of the current window:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Rookie Tutorial (example.com)</title>
<script>
function check(){
if (window.top!=window.self) {
document.write("<p>This window is not the topmost window! Am I in a frame?</p>")
}
else{
document.write("<p>This window is the topmost window!</p>")
}
}
</script>
</head>
<body>
<input type="button" onclick="check()" value="Check window">
</body>
</html>
<html>
<head>
<meta charset="utf-8">
<title>Rookie Tutorial (example.com)</title>
<script>
function check(){
if (window.top!=window.self) {
document.write("<p>This window is not the topmost window! Am I in a frame?</p>")
}
else{
document.write("<p>This window is the topmost window!</p>")
}
}
</script>
</head>
<body>
<input type="button" onclick="check()" value="Check window">
</body>
</html>
Try it Yourself »
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