$(window).scroll() firing on page load

问题:

Is there a way to prevent $(window).scroll() from firing on page load?

Testing the following code in Firefox 4, it fires even when I unplug the mouse.

jQuery(document).ready(function($){    
$(window).scroll(function(){
                console.log("Scroll Fired");
    });
});

回答1:

The scroll event is unrelated to the mouse, it is called whenever a new document scrolling position is set. And arguably that position is set when the document loads (you might load it with an anchor after all), also if the user presses a cursor key on his keyboard. I don't know why you need to ignore the initial scroll event but I guess that you only want to do it if pageYOffset is zero. That's easy:

var oldPageYOffset = 0;
$(window).scroll(function(){
  if (window.pageYOffset != oldPageYOffset)
  {
    oldPageYOffset = window.pageYOffset;
    console.log("Window scrolling changed");
  }
});

Note: MSIE doesn't have window.pageYOffset property so the above will need to be adjusted. Maybe jQuery offers a cross-browser alternative.

回答2:

This was the solution I went for. Any improvements gratefully received.

   var scroll = 0;
    $(window).scroll(function(){
                    if (scroll>0){
                    console.log("Scroll Fired");
                    }
                    scroll++;
    });

回答3:

The scroll event does not fire on every load, only when refreshing a page that was scrolled, or when navigating to an anchor directly.

Many of the answers suggest ignore the first time it's called, which would ignore a valid scroll if the page doesn't get scrolled initially.

//Scroll the page and then reload just the iframe (right click, reload frame)


//Timeout of 1 was not reliable, 10 seemed to be where I tested it, but again, this is not very elegant.
//This will not fire initially
setTimeout(function(){
  $(window).scroll(function(){
     console.log('delayed scroll handler');
  }); 
}, 10); 

//This will fire initially when reloading the page and re-establishing the scroll position
$(window).scroll(function(){
  console.log('regular scroll handler');
});

div {  
  height: 2000px;
  border: 1px solid red;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>
</div>

回答4:

sure, don't load it until after the load. make it a call back for sleep for 500 millis.