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Forked from jtangelder/PreventGhostClick.js
Last active August 29, 2015 14:23
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/**
* Prevent click events after a touchend.
*
* Inspired/copy-paste from this article of Google by Ryan Fioravanti
* https://developers.google.com/mobile/articles/fast_buttons#ghost
*
* USAGE:
* Prevent the click event for an certain element
* ````
* PreventGhostClick(myElement);
* ````
*
* Prevent clicks on the whole document (not recommended!!) *
* ````
* PreventGhostClick(document);
* ````
*
*/
(function(window, document, exportName) {
var coordinates = [];
var threshold = 25;
var timeout = 2500;
// no touch support
if(!("ontouchstart" in window)) {
window[exportName] = function(){};
return;
}
/**
* prevent clicks if they're in a registered XY region
* @param {MouseEvent} ev
*/
function preventGhostClick(ev) {
for (var i = 0; i < coordinates.length; i++) {
var x = coordinates[i][0];
var y = coordinates[i][1];
// within the range, so prevent the click
if (Math.abs(ev.clientX - x) < threshold && Math.abs(ev.clientY - y) < threshold) {
ev.stopPropagation();
ev.preventDefault();
break;
}
}
}
/**
* reset the coordinates array
*/
function resetCoordinates() {
coordinates = [];
}
/**
* remove the first coordinates set from the array
*/
function popCoordinates() {
coordinates.splice(0, 1);
}
/**
* if it is an final touchend, we want to register it's place
* @param {TouchEvent} ev
*/
function registerCoordinates(ev) {
// touchend is triggered on every releasing finger
// changed touches always contain the removed touches on a touchend
// the touches object might contain these also at some browsers (firefox os)
// so touches - changedTouches will be 0 or lower, like -1, on the final touchend
if(ev.touches.length - ev.changedTouches.length <= 0) {
var touch = ev.changedTouches[0];
coordinates.push([touch.clientX, touch.clientY]);
setTimeout(popCoordinates, timeout);
}
}
/**
* prevent click events for the given element
* @param {EventTarget} el
*/
window[exportName] = function(el) {
el.addEventListener("touchstart", resetCoordinates, true);
el.addEventListener("touchend", registerCoordinates, true);
};
document.addEventListener("click", preventGhostClick, true);
})(window, document, 'PreventGhostClick');
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