Hide and then show div depending on screen height or scroll
<p>I am trying to write a script that basically shows a div if the screen height is greater than 750 but hides the div it is less than 750. However, if the screen is less than 750 but the  user scrolls past 750, the div is made visible. Once div is made visible, in either case, it stays that way.</p>

<p>My knowledge is very limited, I'm just starting out, I know what I need to combine in order to achieve this but I haven't been able to figure it out.</p>

<pre><code>$(document).ready(function () {

if (screen.height &lt; 750) {
    $(".contain-grouping").hide();
}
else {

    $(".contain-grouping").show();
}

});
</code></pre>

<p>Can anyone help modify this into what I am trying to achieve?</p>
