Use jQuery to show a div only when scroll position is between 2 points
I'm trying to work out how to get a div (#tips) to appear when the user scrolls into the 2nd quarter of its containing div's height (#wrap), and then have it disappear when the user scrolls into the last quarter. So it would be like this:
1st quarter - #tips is hidden
2nd quarter - #tips is visible 3rd quarter - #tips is visible 4th quarter - #tips is hiddenI'm almost completely new to jQuery but what I've got so far is this:
function addKeyboardNavigation(){
// get the height o开发者_运维知识库f #wrap
var $wrapHeight = $('#wrap').outerHeight()
// get 1/4 of wrapHeight
var $quarterwrapHeight = ($wrapHeight)/4
// get 3/4 of wrapHeight
var $threequarterswrapHeight = 3*($wrapHeight)
// check if we're over a quarter down the page
if( $(window).scrollTop() > $quarterwrapHeight ){
// if we are show keyboardTips
$("#tips").fadeIn("slow");
}
}
This is where I get confused. How can I check if the scroll position is > $quarterwrapHeight but < $threequarterswrapHeight?
To make it run I've been using:
// Run addKeyboardNavigation on scroll
$(window).scroll(function(){
addKeyboardNavigation();
});
Any help or suggestions would be greatly appreciated!
Thanks.
Hi I posted a demo here... the only problem is if your #wrap div isn't tall enough, the top of the window will never get to the 3/4 height, so the tooltip won't fade out. Here is the code:
$(document).ready(function(){
$(window).scroll(function(){
// get the height of #wrap
var h = $('#wrap').height();
var y = $(window).scrollTop();
if( y > (h*.25) && y < (h*.75) ){
// if we are show keyboardTips
$("#tips").fadeIn("slow");
} else {
$('#tips').fadeOut('slow');
}
});
})
I used height()
but you can use outerHeight()
... I forgot to change it in the demo because originally I was using the body
instead of the #wrap
.
Another problem would be if the #wrap isn't located at the top of the page. If it's further down, then you'll have to subtract it's position on the page from the scrollTop
:
var y = $(window).scrollTop() - $('#wrap').position().top;
How about:
if(($(window).scrollTop() > $quarterwrapHeight) && ($(window).scrollTop() < $threequarterswrapHeight)){
$("#tips").fadeIn("slow");
} else {
$("#tips").fadeOut("slow");
}
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