Question

I need to know how I can get the first element that is visible in the browser view.

I am implementing a custom scroller. however when the user uses the mouse to scroll my custom scroller messes up. I need to find the visible divs in the visible area in the browser after scrolling, so I will be able to scroll to the right element.

here is the structure of my page:

<div class="page">

    <div id="scroller" class="news-scroller">
         <div ><span id="up"></span></div>
         <div ><span id="down"></span></div>
    </div>

    <div class="news">
    </div>
    <div class="news">
    </div>
    ....
</div>

I am using the scroller #up and #down to scroll to the previous or next div.news. (I use scrollTo plugin) but after using the mouse for scroll I need to understand which div.news is the first visible element in the page to reset my custom scroller.

Here is my code in case it helps:

var current = $(".news").eq(0);

$("#down").click(function(){
    if(current.next().size() > 0)
    {
        current = current.next();
        $.scrollTo("#"+current.attr("id"), 800);     

    }
    else  if(current.next().size() <= 0)
    {
        return
    }
});

$("#up").click(function(){
    if(current.prev().size() > 0)
    {
        current=current.prev();
        $.scrollTo("#"+current.attr("id"), 800);
    }
    else  if(current.prev().size() <= 0)
    {
        return;
}
});

and here is the example page.

Answer 1

Following code will tell you if element is completely visible.

function isElementVisisble(element) {
          element = $(element);
           var parent = $(window);
        var containerLeft = parent.parent().scrollLeft();
        var containerRight = containerLeft + parent.parent().width();
        var elemLeft = element.offsetLeft;
        var elemRight = elemLeft + $(element).width();
        if (elemLeft < containerLeft || elemRight > containerRight) {
            return false;
        }
         return true;
    }

You can use

   var firstVisibleElem;
    jQuery("*").each(function(){
        if(isElementVisisble(this)){
             firstVisibleElem= this;
              return false;
         }
    });