jQuery parallax lags inChrome and Safari

Question

My parallax effect works well in firefox, but in chrome and safari it doesn't work well. Here's a jsfiddle.net/n5kjK/1/ that describes the structure of my page.

My HTML

<article>
    <div class="thumbnail-container">
        <img src="http://placehold.it/300x200&text=thumbnail"/>
    </div>

    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris sit amet leo non erat aliquam pellentesque. Duis et dictum velit. Curabitur blandit odio quis luctus ultrices. Maecenas venenatis erat in eros feugiat imperdiet. Duis ultricies nulla quis eros eleifend sagittis.
</article>
<article>
    <div class="thumbnail-container">
        <img src="http://placehold.it/300x200&text=thumbnail"/>
    </div>
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris sit amet leo non erat aliquam pellentesque. Duis et dictum velit. Curabitur blandit odio quis luctus ultrices. Maecenas venenatis erat in eros feugiat imperdiet. Duis ultricies nulla quis eros eleifend sagittis.
</article>
<article>
    <div class="thumbnail-container">
        <img src="http://placehold.it/300x200&text=thumbnail"/>
    </div>
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris sit amet leo non erat aliquam pellentesque. Duis et dictum velit. Curabitur blandit odio quis luctus ultrices. Maecenas venenatis erat in eros feugiat imperdiet. Duis ultricies nulla quis eros eleifend sagittis.
</article>
<article>
    <div class="thumbnail-container">
        <img src="http://placehold.it/300x200&text=thumbnail"/>
    </div>
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris sit amet leo non erat aliquam pellentesque. Duis et dictum velit. Curabitur blandit odio quis luctus ultrices. Maecenas venenatis erat in eros feugiat imperdiet. Duis ultricies nulla quis eros eleifend sagittis.
</article>
<article>
    <div class="thumbnail-container">
        <img src="http://placehold.it/300x200&text=thumbnail"/>
    </div>
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris sit amet leo non erat aliquam pellentesque. Duis et dictum velit. Curabitur blandit odio quis luctus ultrices. Maecenas venenatis erat in eros feugiat imperdiet. Duis ultricies nulla quis eros eleifend sagittis.
</article>

My JS

$(function(){
    $(window).on('scroll', function(e) {
        $('.ciao').html("ciao");
        var windowScrollTop=$(this).scrollTop();
        parallax(windowScrollTop);      
    }); 
});

function parallax(windowScrollTop) {
    $('.thumbnail-container img').each(function(index){
    var dif=windowScrollTop-$(this).parent().position().top;
        var scrollSlow = dif *(0.5);
        if(dif>=0)
            $(this).css('top', (scrollSlow) + 'px');
     });
}

and my CSS

article{
    width:100%;
    text-align:justify;
}
.thumbnail-container{
  position: relative;
  height: 350px;
  overflow: hidden;
 }

.thumbnail-container img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: auto;
}

Where is the problem?

Thanks!!

Answer 1

The problem is the mouse scroll is not smooth. Use this plugin to override default mouse scroll.