Run function once per event burst with jQuery

问题:

I'm using jQuery to listen to DOMSubtreeModified event, and then execute a function. What I need is a way to only run a function once per event burst. So in this case, the event will only run after 1 second, and again after 3 seconds. What is the best way to do this?

jQuery

$(function(){

    setTimeout(function(){
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
    },1000);

    setTimeout(function(){
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
    },3000);

    $('#container').bind('DOMSubtreeModified',function(){
        console.log('event');
        functionToRun();
    });

});

HTML

<div id="container"></div>

Update
The setTimeout function are there just to emulate my problem. I need a solution without changing the setTimeout code. The problem I'm having is that I get burst of DOMSubtreeModified events, and I need to get only one per burst.

回答1:

Alternate method, which will control the rate of any function.

// Control the call rate of a function.
//  Note that this version makes no attempt to handle parameters
//  It always induces a delay, which makes the state tracking much easier.
//    This makes it only useful for small time periods, however.
//    Just clearing a flag after the timeout won't work, because we want
//    to do the the routine at least once if was called during the wait period.
throttle = function(call, timeout) {
  var my = function() {
    if (!my.handle) {
      my.handle = setTimeout(my.rightNow, timeout);
    }
  };
  my.rightNow = function() {
    if (my.handle) {
      clearTimeout(my.handle);
      my.handle = null;
    }
    call();
  };
  return my;
};

回答2:

Solved it myself.

$(function(){

    setTimeout(function(){
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
    },1000);

    setTimeout(function(){
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
    },1100);

    setTimeout(function(){
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
        $('#container')[0].innerHTML = 'test';
    },3000);

    addDivListener();

 });

 function addDivListener() {
    $('#container').bind('DOMSubtreeModified',function(){
        functionToRun();
        $(this).unbind('DOMSubtreeModified');
        setTimeout(addDivListener,10);  
    });
 }

 function functionToRun(){
    console.log('event');
 }

This prints out event 3 times in the Firebug console, and is accurate down to 100 ms.

回答3:

try using one() handler

documentation

回答4:

This seems to be what you're looking for:

$(
  function()
  {
    setTimeout 
    (
      StartWatching,
      1000
    );
  }
);

function StartWatching()
{
  $('#container')
     .bind(
            'DOMSubtreeModified',
            function()
            {
              console.log('event');
              StopWatchingAndStartAgainLater();
            }
          );
}

function StopWatching()
{
  $('#container')
      .unbind('DOMSubtreeModified');
}

function StopWatchingAndStartAgainLater()
{
  StopWatching();
  setTimeout
  (
    StartWatching,
    3000
  );
}

This enforces the following flow:

Document.Ready
Create DOM watching event after one second
On event, turn off event and recreate it after three seconds, rinse, repeat