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Sometimes it can be very useful to hide the scrollbar of elements in a website and only show it when the user really needs it. The real-time activity feed in Facebook is an example for such a behavior. Today we want to show you how to use jScrollPane and extend it with the functionality to hide the scrollbar and show it on hover.
jScrollPane was created by Kevin Luck and you can read more about it here:
jScrollPane – cross browser styleable scrollbars with jQuery and CSS
The Markup
An example for the markup used in our demos is the following:
<div id="jp-container" class="jp-container"> <!-- content --> </div>
The jp-container will be our scrollable content area.
The CSS
Besides the style for the custom scrollbar of jScrollPane, we will have the following style for our container:
.jp-container{
width:500px;
height:400px;
position:relative;
background:#fff;
border:1px solid #D8DFEA;
float:left;
}
The JavaScript
We are going to extend the jScrollPane plugin with the new functionality of showing and hiding the scrollbar:
// the element we want to apply the jScrollPane
var $el = $('#jp-container').jScrollPane({
verticalGutter : -16
}),
// the extension functions and options
extensionPlugin = {
extPluginOpts : {
// speed for the fadeOut animation
mouseLeaveFadeSpeed : 500,
// scrollbar fades out after
// hovertimeout_t milliseconds
hovertimeout_t : 1000,
// if set to false, the scrollbar will
// be shown on mouseenter and hidden on
// mouseleave
// if set to true, the same will happen,
// but the scrollbar will be also hidden
// on mouseenter after "hovertimeout_t" ms
// also, it will be shown when we start to
// scroll and hidden when stopping
useTimeout : false,
// the extension only applies for devices
// with width > deviceWidth
deviceWidth : 980
},
hovertimeout : null,
// timeout to hide the scrollbar
isScrollbarHover: false,
// true if the mouse is over the scrollbar
elementtimeout : null,
// avoids showing the scrollbar when moving
// from inside the element to outside, passing
// over the scrollbar
isScrolling : false,
// true if scrolling
addHoverFunc : function() {
// run only if the window has a width bigger than deviceWidth
if( $(window).width() <= this.extPluginOpts.deviceWidth ) return false;
var instance = this;
// functions to show / hide the scrollbar
$.fn.jspmouseenter = $.fn.show;
$.fn.jspmouseleave = $.fn.fadeOut;
// hide the jScrollPane vertical bar
var $vBar = this.getContentPane().siblings('.jspVerticalBar').hide();
/*
* mouseenter / mouseleave events on the main element
* also scrollstart / scrollstop
* @James Padolsey : http://james.padolsey.com/javascript/special-scroll-events-for-jquery/
*/
$el.bind('mouseenter.jsp',function() {
// show the scrollbar
$vBar.stop( true, true ).jspmouseenter();
if( !instance.extPluginOpts.useTimeout ) return false;
// hide the scrollbar after hovertimeout_t ms
clearTimeout( instance.hovertimeout );
instance.hovertimeout = setTimeout(function() {
// if scrolling at the moment don't hide it
if( !instance.isScrolling )
$vBar.stop( true, true ).jspmouseleave( instance.extPluginOpts.mouseLeaveFadeSpeed || 0 );
}, instance.extPluginOpts.hovertimeout_t );
}).bind('mouseleave.jsp',function() {
// hide the scrollbar
if( !instance.extPluginOpts.useTimeout )
$vBar.stop( true, true ).jspmouseleave( instance.extPluginOpts.mouseLeaveFadeSpeed || 0 );
else {
clearTimeout( instance.elementtimeout );
if( !instance.isScrolling )
$vBar.stop( true, true ).jspmouseleave( instance.extPluginOpts.mouseLeaveFadeSpeed || 0 );
}
});
if( this.extPluginOpts.useTimeout ) {
$el.bind('scrollstart.jsp', function() {
// when scrolling show the scrollbar
clearTimeout( instance.hovertimeout );
instance.isScrolling = true;
$vBar.stop( true, true ).jspmouseenter();
}).bind('scrollstop.jsp', function() {
// when stop scrolling hide the
// scrollbar (if not hovering it at the moment)
clearTimeout( instance.hovertimeout );
instance.isScrolling = false;
instance.hovertimeout = setTimeout(function() {
if( !instance.isScrollbarHover )
$vBar.stop( true, true ).jspmouseleave( instance.extPluginOpts.mouseLeaveFadeSpeed || 0 );
}, instance.extPluginOpts.hovertimeout_t );
});
// wrap the scrollbar
// we need this to be able to add
// the mouseenter / mouseleave events
// to the scrollbar
var $vBarWrapper = $('<div/>').css({
position : 'absolute',
left : $vBar.css('left'),
top : $vBar.css('top'),
right : $vBar.css('right'),
bottom : $vBar.css('bottom'),
width : $vBar.width(),
height : $vBar.height()
}).bind('mouseenter.jsp',function() {
clearTimeout( instance.hovertimeout );
clearTimeout( instance.elementtimeout );
instance.isScrollbarHover = true;
// show the scrollbar after 100 ms.
// avoids showing the scrollbar when moving
// from inside the element to outside,
// passing over the scrollbar
instance.elementtimeout = setTimeout(function() {
$vBar.stop( true, true ).jspmouseenter();
}, 100 );
}).bind('mouseleave.jsp',function() {
// hide the scrollbar after hovertimeout_t
clearTimeout( instance.hovertimeout );
instance.isScrollbarHover = false;
instance.hovertimeout = setTimeout(function() {
// if scrolling at the moment
// don't hide it
if( !instance.isScrolling )
$vBar.stop( true, true ).jspmouseleave( instance.extPluginOpts.mouseLeaveFadeSpeed || 0 );
}, instance.extPluginOpts.hovertimeout_t );
});
$vBar.wrap( $vBarWrapper );
}
}
},
// the jScrollPane instance
jspapi = $el.data('jsp');
// extend the jScollPane by merging
$.extend( true, jspapi, extensionPlugin );
jspapi.addHoverFunc();
And that’s it! I hope you liked this little extension and find it useful!
