滚动100px后将div位置设置为固定？

Question

I tried to use the following function in order to set the div's position to 100 px from top after scrolling 100 px.

<script src="http://code.jquery.com/jquery-latest.js"></script>
<script type="text/javascript">
$(window).scroll(function(){
    $("#header").css("top",Math.max(0,100-$(this).scrollTop()));
});
</script>
<div class="header"  style="position:fixed;top:100px;background-color:red">something</div>

it is not working(the div stick to it's fixed position). it seems that the function is not relating to the div. what is my problem ?

Answer 1

Your problem ist that your div has the class header, not the id . Try <div id="header" style="position:fixed;top:100px;background-color:red">something</div>

Answer 2

$(document).ready(function(){
    $('.header').scroll(function(){
        $(this).css("top",Math.max(0,100-$(this).scrollTop()));
    });
});