Mouse wheel programming_javascript skills

I didn't notice this scroll wheel before, but I saw an article here about it: http://www.javascriptsearch.com/guides/Advanced/articles/JSMouseScrolling.html

I put it Turned around. If it is used in actual applications, sometimes it is quite useful. The main thing is to get whether the scroll wheel rolls up or down.

Commented code

function handle(delta) {
if (delta < 0)
…;
else
…;
}

/**Event handler
*/
function wheel(event){
var delta = 0;
if (!event) /* For IE. */
event = window.event;
if ( event.wheelDelta) { /* IE or Opera. */
delta = event.wheelDelta/120;
/**In Opera9, event handling is different from IE
*/
if (window.opera)
delta = - delta;
} else if (event.detail) { /**Compatible with Mozilla.*/
/**In Mozilla, sign of delta is different than in IE.
 * Also, delta is multiple of 3.
 */
delta = -event.detail/3;
}
/**If the increment is not equal to 0, it will trigger
* The main function is to test whether the wheel rolls up or down
*/
if (delta)
handle(delta);
}

/**initialization*/
if (window. addEventListener)
/**Mozilla's DOM-based scroll wheel events **/
window.addEventListener('DOMMouseScroll', wheel, false);
/**IE/Opera.*/
window.onmousewheel = document.onmousewheel = wheel;

In the above code, the code in the handler function is what you need to write. It has a parameter -delta. In fact, it is just the code to determine whether the mouse is scrolling up or down at the moment. As shown below,

<?xml version="1.0" encoding="UTF-8"?> <title> mousewheel delta - http://www.never-online.net </title> <meta http-equiv="ImageToolbar" content="no"> <meta name="author" content="never-online, BlueDestiny"> <meta name="keywords" content="never modules, Mozilla CSS, C#, .net, Refercence, BlueDestiny, never-online"> <meta name="description" content="BlueDestiny, never-online"> <meta name="title" content=" - http://www.never-online.net"> <meta name="creator.name" content="never-online, BlueDestiny"> <style type="text/css" media="all" title="Default"> </style> <div id="delta"> </div>Scroll mouse wheel to see delta here.
[Ctrl A select all Note: If you need to introduce external Js, you need to refresh to execute

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