How to prevent calling of en event handler twice on fast clicks?

Question

There is a button and when user clicks on button, some data is saved to back-end. Issue is when user clicks on button very quickly, event handler is getting executed multiple times.

This is the code

var x = 1; $('#button').click(function() {   // Do something   // Save some data on network   x++;   console.log(x); }); 

I want this handler to get executed when user clicks on button just once. Even In case of double or tripple click, this should get executed only once. I just want to avoid quick clicks, this handler can get executed again ofcourse

I have multiple solutions in my mind like

1. Define a global variable like IS_BUTTON_HANDLER_WORKING = false and when you enter the handler set it to true and in the end set it to false again. And check if it is true just return from the function.

2. Detach the handler in the beginning and reattach in the end.

Consider you have 25 buttons in your application. What should be the best approach to implement this.

Take a look at this Fiddle

Solution

$('#button').click(function() {    $(this).attr('disabled', true);   // Do something   // Save some data on network   $(this).removeAttr('disabled'); }); 

Using this, we are sure that our next handler will get executed only when previous execution has been done completely.

Answer 1

David Walsh has a great solution.

// Returns a function, that, as long as it continues to be invoked, will not // be triggered. The function will be called after it stops being called for // N milliseconds. If `immediate` is passed, trigger the function on the // leading edge, instead of the trailing. function debounce(func, wait, immediate) {     var timeout;     return function() {         var context = this, args = arguments;         var later = function() {             timeout = null;             if (!immediate) func.apply(context, args);         };         var callNow = immediate && !timeout;         clearTimeout(timeout);         timeout = setTimeout(later, wait);         if (callNow) func.apply(context, args);     }; }; 

Answer 2

There are multiple ways of dealing with this:

You can disable/hide the button after the click:

$('#button').attr("disabled", true); 

You can also set a timeout on each click to ensure it does not execute again:

var x, y = 1;  $('#button').click(function() {   if (x) clearTimeout(x);   x = setTimeout(function() {      // do the work here      y++;      console.log(y);      // ----------------   }, 1000); }); 

So each time the button is clicked, it will only actually execute the code after a 1000 milliseconds, if the button is clicked in rapid succession, the timeout will just be cleared and start over again.

_{note that the above is untested}

Personally I think the disabled solution is the best as it indicates to the user that he has clicked and something is happening, you can even show a loader next to the button as well.