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in Technique[技术] by (71.8m points)

javascript - keydown on body?

I want to get alerted whenever I press a key.

I've tried:

$('body').live('keyup', function() {
     alert('testing');
});

But it doesn't work, could it be because of the selector?

UPDATE:

Here is my code:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
        <title>TODO supply a title</title>
        <script type="text/javascript" src="../system/media/js/jquery/jquery.js"></script>
        <script type="text/javascript">  
            $(document).ready(function() {
                $('body').live('keyup', function() {
                    alert('testing');
                });   
            });   
        </script>
    </head>
    <body>
        <p>
            TODO write content
        </p>
    </body>
</html>

It doesn't alert me when I press something although it works when I replace keyup with mouseover and mouse over TODO write content

Why doesn't it work?

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1 Reply

0 votes
by (71.8m points)

Try using $("html") or $("*") instead of $("body"). In order for the keyUp event on body to fire, the body node or one of its children must be focused. You can accomplish this in your example by adding a text input and focusing the mouse to that input. What you really want is to capture any key press, so $("html") should work.

Edit: I think your example might work, but in any case, to run the logic conditionally you might try this:

if ($(document.body).is(".focusOnKeypress")) {
   $("html").live(...);
}

Or, I think this will also work:

$("body:not(.noFocusOnKeypress)").parent("html").live(...);

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