Personalizar la barra de desplazamiento (scrollbar) con jScrollPane

jScrollPane es un script de jQuery que permite cambiar la barra de desplazamiento del blog, es decir, el scrollbar del navegador.
Si bien podemos usar CSS para modificarlo, el problema es que no está estandarizado, por lo que con CSS sólo podemos hacerlo funcionar en Chrome y Safari; y en el caso de Internet Explorer también tiene su propio código pero obviamente sólo funciona en ese navegador (no sé en cuáles versiones). Así que lo que haremos a continuación es darle un nuevo aspecto al scrollbar pero usando jQuery, de esta manera el cambio será visible en todos los navegadores.

Puedes ver un ejemplo en este blog de pruebas, verás que la barra de desplazamiento tiene otra forma y color.

Para cambiar el scrollbar de tu blog primero entra en Plantilla | Edición de HTML y antes de </head> pega este código:

<script src='//ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js' type='text/javascript'/>

<style>
.jspContainer {overflow: hidden;position: relative;}.jspPane {position: absolute;}
.jspVerticalBar {position: absolute;top: 0;right: 0;width: 16px;height: 100%;background: #ccc;}
.jspHorizontalBar {position: absolute;bottom: 0;left: 0;width: 100%;height: 16px;background: #ccc;}
.jspVerticalBar *,.jspHorizontalBar * {margin: 0;padding: 0;}
.jspCap {display: none;}.jspHorizontalBar .jspCap {float: left;}

.jspTrack {
background: #dde; /* Color de fondo de la barra */
position: relative;
}
.jspDrag {
background: #bbd; /* Color del botón de desplazamiento */
position: relative;
top: 0;
left: 0;
cursor: pointer;
}
.jspHorizontalBar .jspTrack,
.jspHorizontalBar .jspDrag {
float: left;
height: 100%;
}
.jspArrow {
background: #50506d; /*Color de los límites */
text-indent: -20000px;
display: block;
cursor: pointer;
}
.jspArrow.jspDisabled {
cursor: default;
background: #80808d; /*Color de los límites cuando el botón llega hasta ellos */
}
.jspVerticalBar .jspArrow {
height: 16px;
}
.jspHorizontalBar .jspArrow {
width: 16px;
float: left;
height: 100%;
}
.jspVerticalBar .jspArrow:focus {outline: none;}.jspCorner {background: #eeeef4;float: left;height: 100%;}* html .jspCorner {margin: 0 -3px 0 0;}
html, body {
height: 100%;
margin: 0;
padding: 0;
}
#blog-container {
height: 100%;
margin: 0;
padding: 0;
overflow: auto;
}
</style>
<script>
//<![CDATA[
/*! Copyright (c) 2013 Brandon Aaron (http://brandonaaron.net)
* Licensed under the MIT License (LICENSE.txt).
* Version: 3.1.3
*/

(function (factory) {
if ( typeof define === 'function' && define.amd ) {
define(['jquery'], factory);
} else if (typeof exports === 'object') {
module.exports = factory;
} else {
// Browser globals
factory(jQuery);
}
}(function ($) {

var toFix = ['wheel', 'mousewheel', 'DOMMouseScroll', 'MozMousePixelScroll'];
var toBind = 'onwheel' in document || document.documentMode >= 9 ? ['wheel'] : ['mousewheel', 'DomMouseScroll', 'MozMousePixelScroll'];
var lowestDelta, lowestDeltaXY;

if ( $.event.fixHooks ) {
for ( var i = toFix.length; i; ) {
$.event.fixHooks[ toFix[--i] ] = $.event.mouseHooks;
}
}

$.event.special.mousewheel = {
setup: function() {
if ( this.addEventListener ) {
for ( var i = toBind.length; i; ) {
this.addEventListener( toBind[--i], handler, false );
}
} else {
this.onmousewheel = handler;
}
},

teardown: function() {
if ( this.removeEventListener ) {
for ( var i = toBind.length; i; ) {
this.removeEventListener( toBind[--i], handler, false );
}
} else {
this.onmousewheel = null;
}
}
};

$.fn.extend({
mousewheel: function(fn) {
return fn ? this.bind("mousewheel", fn) : this.trigger("mousewheel");
},

unmousewheel: function(fn) {
return this.unbind("mousewheel", fn);
}
});

function handler(event) {
var orgEvent = event || window.event,
args = [].slice.call(arguments, 1),
delta = 0,
deltaX = 0,
deltaY = 0,
absDelta = 0,
absDeltaXY = 0,
fn;
event = $.event.fix(orgEvent);
event.type = "mousewheel";
if ( orgEvent.wheelDelta ) { delta = orgEvent.wheelDelta; }
if ( orgEvent.detail ) { delta = orgEvent.detail * -1; }
if ( orgEvent.deltaY ) {
deltaY = orgEvent.deltaY * -1;
delta = deltaY;
}
if ( orgEvent.deltaX ) {
deltaX = orgEvent.deltaX;
delta = deltaX * -1;
}
if ( orgEvent.wheelDeltaY !== undefined ) { deltaY = orgEvent.wheelDeltaY; }
if ( orgEvent.wheelDeltaX !== undefined ) { deltaX = orgEvent.wheelDeltaX * -1; }
absDelta = Math.abs(delta);
if ( !lowestDelta || absDelta < lowestDelta ) { lowestDelta = absDelta; }
absDeltaXY = Math.max(Math.abs(deltaY), Math.abs(deltaX));
if ( !lowestDeltaXY || absDeltaXY < lowestDeltaXY ) { lowestDeltaXY = absDeltaXY; }
fn = delta > 0 ? 'floor' : 'ceil';
delta = Math[fn](delta / lowestDelta);
deltaX = Math[fn](deltaX / lowestDeltaXY);
deltaY = Math[fn](deltaY / lowestDeltaXY);
args.unshift(event, delta, deltaX, deltaY);
return ($.event.dispatch || $.event.handle).apply(this, args);
}
}));

/*
* jScrollPane - v2.0.0beta5 - 2010-09-18
* http://jscrollpane.kelvinluck.com/
* Copyright (c) 2010 Kelvin Luck
* Dual licensed under the MIT and GPL licenses.
*/
(function(b,a,c){b.fn.jScrollPane=function(f){function d(C,L){var au,N=this,V,ah,v,aj,Q,W,y,q,av,aB,ap,i,H,h,j,X,R,al,U,t,A,am,ac,ak,F,l,ao,at,x,aq,aE,g,aA,ag=true,M=true,aD=false,k=false,Z=b.fn.mwheelIntent?"mwheelIntent.jsp":"mousewheel.jsp";aE=C.css("paddingTop")+" "+C.css("paddingRight")+" "+C.css("paddingBottom")+" "+C.css("paddingLeft");g=(parseInt(C.css("paddingLeft"))||0)+(parseInt(C.css("paddingRight"))||0);an(L);function an(aH){var aL,aK,aJ,aG,aF,aI;au=aH;if(V==c){C.css({overflow:"hidden",padding:0});ah=C.innerWidth()+g;v=C.innerHeight();C.width(ah);V=b('<div class="jspPane" />').wrap(b('<div class="jspContainer" />').css({width:ah+"px",height:v+"px"}));C.wrapInner(V.parent());aj=C.find(">.jspContainer");V=aj.find(">.jspPane");V.css("padding",aE)}else{C.css("width",null);aI=C.outerWidth()+g!=ah||C.outerHeight()!=v;if(aI){ah=C.innerWidth()+g;v=C.innerHeight();aj.css({width:ah+"px",height:v+"px"})}aA=V.innerWidth();if(!aI&&V.outerWidth()==Q&&V.outerHeight()==W){if(aB||av){V.css("width",aA+"px");C.css("width",(aA+g)+"px")}return}V.css("width",null);C.css("width",(ah)+"px");aj.find(">.jspVerticalBar,>.jspHorizontalBar").remove().end()}aL=V.clone().css("position","absolute");aK=b('<div style="width:1px; position: relative;" />').append(aL);b("body").append(aK);Q=Math.max(V.outerWidth(),aL.outerWidth());aK.remove();W=V.outerHeight();y=Q/ah;q=W/v;av=q>1;aB=y>1;if(!(aB||av)){C.removeClass("jspScrollable");V.css({top:0,width:aj.width()-g});n();D();O();w();af()}else{C.addClass("jspScrollable");aJ=au.maintainPosition&&(H||X);if(aJ){aG=ay();aF=aw()}aC();z();E();if(aJ){K(aG);J(aF)}I();ad();if(au.enableKeyboardNavigation){P()}if(au.clickOnTrack){p()}B();if(au.hijackInternalLinks){m()}}if(au.autoReinitialise&&!aq){aq=setInterval(function(){an(au)},au.autoReinitialiseDelay)}else{if(!au.autoReinitialise&&aq){clearInterval(aq)}}C.trigger("jsp-initialised",[aB||av])}function aC(){if(av){aj.append(b('<div class="jspVerticalBar" />').append(b('<div class="jspCap jspCapTop" />'),b('<div class="jspTrack" />').append(b('<div class="jspDrag" />').append(b('<div class="jspDragTop" />'),b('<div class="jspDragBottom" />'))),b('<div class="jspCap jspCapBottom" />')));R=aj.find(">.jspVerticalBar");al=R.find(">.jspTrack");ap=al.find(">.jspDrag");if(au.showArrows){am=b('<a class="jspArrow jspArrowUp" />').bind("mousedown.jsp",az(0,-1)).bind("click.jsp",ax);ac=b('<a class="jspArrow jspArrowDown" />').bind("mousedown.jsp",az(0,1)).bind("click.jsp",ax);if(au.arrowScrollOnHover){am.bind("mouseover.jsp",az(0,-1,am));ac.bind("mouseover.jsp",az(0,1,ac))}ai(al,au.verticalArrowPositions,am,ac)}t=v;aj.find(">.jspVerticalBar>.jspCap:visible,>.jspVerticalBar>.jspArrow").each(function(){t-=b(this).outerHeight()});ap.hover(function(){ap.addClass("jspHover")},function(){ap.removeClass("jspHover")}).bind("mousedown.jsp",function(aF){b("html").bind("dragstart.jsp selectstart.jsp",function(){return false});ap.addClass("jspActive");var s=aF.pageY-ap.position().top;b("html").bind("mousemove.jsp",function(aG){S(aG.pageY-s,false)}).bind("mouseup.jsp mouseleave.jsp",ar);return false});o()}}function o(){al.height(t+"px");H=0;U=au.verticalGutter+al.outerWidth();V.width(ah-U-g);if(R.position().left==0){V.css("margin-left",U+"px")}}function z(){if(aB){aj.append(b('<div class="jspHorizontalBar" />').append(b('<div class="jspCap jspCapLeft" />'),b('<div class="jspTrack" />').append(b('<div class="jspDrag" />').append(b('<div class="jspDragLeft" />'),b('<div class="jspDragRight" />'))),b('<div class="jspCap jspCapRight" />')));ak=aj.find(">.jspHorizontalBar");F=ak.find(">.jspTrack");h=F.find(">.jspDrag");if(au.showArrows){at=b('<a class="jspArrow jspArrowLeft" />').bind("mousedown.jsp",az(-1,0)).bind("click.jsp",ax);x=b('<a class="jspArrow jspArrowRight" />').bind("mousedown.jsp",az(1,0)).bind("click.jsp",ax);
if(au.arrowScrollOnHover){at.bind("mouseover.jsp",az(-1,0,at));x.bind("mouseover.jsp",az(1,0,x))}ai(F,au.horizontalArrowPositions,at,x)}h.hover(function(){h.addClass("jspHover")},function(){h.removeClass("jspHover")}).bind("mousedown.jsp",function(aF){b("html").bind("dragstart.jsp selectstart.jsp",function(){return false});h.addClass("jspActive");var s=aF.pageX-h.position().left;b("html").bind("mousemove.jsp",function(aG){T(aG.pageX-s,false)}).bind("mouseup.jsp mouseleave.jsp",ar);return false});l=aj.innerWidth();ae()}else{}}function ae(){aj.find(">.jspHorizontalBar>.jspCap:visible,>.jspHorizontalBar>.jspArrow").each(function(){l-=b(this).outerWidth()});F.width(l+"px");X=0}function E(){if(aB&&av){var aF=F.outerHeight(),s=al.outerWidth();t-=aF;b(ak).find(">.jspCap:visible,>.jspArrow").each(function(){l+=b(this).outerWidth()});l-=s;v-=s;ah-=aF;F.parent().append(b('<div class="jspCorner" />').css("width",aF+"px"));o();ae()}if(aB){V.width((aj.outerWidth()-g)+"px")}W=V.outerHeight();q=W/v;if(aB){ao=1/y*l;if(ao>au.horizontalDragMaxWidth){ao=au.horizontalDragMaxWidth}else{if(ao<au.horizontalDragMinWidth){ao=au.horizontalDragMinWidth}}h.width(ao+"px");j=l-ao;ab(X)}if(av){A=1/q*t;if(A>au.verticalDragMaxHeight){A=au.verticalDragMaxHeight}else{if(A<au.verticalDragMinHeight){A=au.verticalDragMinHeight}}ap.height(A+"px");i=t-A;aa(H)}}function ai(aG,aI,aF,s){var aK="before",aH="after",aJ;if(aI=="os"){aI=/Mac/.test(navigator.platform)?"after":"split"}if(aI==aK){aH=aI}else{if(aI==aH){aK=aI;aJ=aF;aF=s;s=aJ}}aG[aK](aF)[aH](s)}function az(aF,s,aG){return function(){G(aF,s,this,aG);this.blur();return false}}function G(aH,aF,aK,aJ){aK=b(aK).addClass("jspActive");var aI,s=function(){if(aH!=0){T(X+aH*au.arrowButtonSpeed,false)}if(aF!=0){S(H+aF*au.arrowButtonSpeed,false)}},aG=setInterval(s,au.arrowRepeatFreq);s();aI=aJ==c?"mouseup.jsp":"mouseout.jsp";aJ=aJ||b("html");aJ.bind(aI,function(){aK.removeClass("jspActive");clearInterval(aG);aJ.unbind(aI)})}function p(){w();if(av){al.bind("mousedown.jsp",function(aH){if(aH.originalTarget==c||aH.originalTarget==aH.currentTarget){var aG=b(this),s=setInterval(function(){var aI=aG.offset(),aJ=aH.pageY-aI.top;if(H+A<aJ){S(H+au.trackClickSpeed)}else{if(aJ<H){S(H-au.trackClickSpeed)}else{aF()}}},au.trackClickRepeatFreq),aF=function(){s&&clearInterval(s);s=null;b(document).unbind("mouseup.jsp",aF)};b(document).bind("mouseup.jsp",aF);return false}})}if(aB){F.bind("mousedown.jsp",function(aH){if(aH.originalTarget==c||aH.originalTarget==aH.currentTarget){var aG=b(this),s=setInterval(function(){var aI=aG.offset(),aJ=aH.pageX-aI.left;if(X+ao<aJ){T(X+au.trackClickSpeed)}else{if(aJ<X){T(X-au.trackClickSpeed)}else{aF()}}},au.trackClickRepeatFreq),aF=function(){s&&clearInterval(s);s=null;b(document).unbind("mouseup.jsp",aF)};b(document).bind("mouseup.jsp",aF);return false}})}}function w(){F&&F.unbind("mousedown.jsp");al&&al.unbind("mousedown.jsp")}function ar(){b("html").unbind("dragstart.jsp selectstart.jsp mousemove.jsp mouseup.jsp mouseleave.jsp");ap&&ap.removeClass("jspActive");h&&h.removeClass("jspActive")}function S(s,aF){if(!av){return}if(s<0){s=0}else{if(s>i){s=i}}if(aF==c){aF=au.animateScroll}if(aF){N.animate(ap,"top",s,aa)}else{ap.css("top",s);aa(s)}}function aa(aF){if(aF==c){aF=ap.position().top}aj.scrollTop(0);H=aF;var aI=H==0,aG=H==i,aH=aF/i,s=-aH*(W-v);if(ag!=aI||aD!=aG){ag=aI;aD=aG;C.trigger("jsp-arrow-change",[ag,aD,M,k])}u(aI,aG);V.css("top",s);C.trigger("jsp-scroll-y",[-s,aI,aG])}function T(aF,s){if(!aB){return}if(aF<0){aF=0}else{if(aF>j){aF=j}}if(s==c){s=au.animateScroll}if(s){N.animate(h,"left",aF,ab)}else{h.css("left",aF);ab(aF)}}function ab(aF){if(aF==c){aF=h.position().left}aj.scrollTop(0);X=aF;var aI=X==0,aH=X==j,aG=aF/j,s=-aG*(Q-ah);if(M!=aI||k!=aH){M=aI;k=aH;C.trigger("jsp-arrow-change",[ag,aD,M,k])}r(aI,aH);V.css("left",s);C.trigger("jsp-scroll-x",[-s,aI,aH])}function u(aF,s){if(au.showArrows){am[aF?"addClass":"removeClass"]("jspDisabled");ac[s?"addClass":"removeClass"]("jspDisabled")}}function r(aF,s){if(au.showArrows){at[aF?"addClass":"removeClass"]("jspDisabled");
x[s?"addClass":"removeClass"]("jspDisabled")}}function J(s,aF){var aG=s/(W-v);S(aG*i,aF)}function K(aF,s){var aG=aF/(Q-ah);T(aG*j,s)}function Y(aN,aL,aF){var aJ,aH,s=0,aG,aK,aM;try{aJ=b(aN)}catch(aI){return}aH=aJ.outerHeight();aj.scrollTop(0);while(!aJ.is(".jspPane")){s+=aJ.position().top;aJ=aJ.offsetParent();if(/^body|html$/i.test(aJ[0].nodeName)){return}}aG=aw();aK=aG+v;if(s<aG||aL){aM=s-au.verticalGutter}else{if(s+aH>aK){aM=s-v+aH+au.verticalGutter}}if(aM){J(aM,aF)}}function ay(){return -V.position().left}function aw(){return -V.position().top}function ad(){aj.unbind(Z).bind(Z,function(aI,aJ,aH,aF){var aG=X,s=H;T(X+aH*au.mouseWheelSpeed,false);S(H-aF*au.mouseWheelSpeed,false);return aG==X&&s==H})}function n(){aj.unbind(Z)}function ax(){return false}function I(){V.unbind("focusin.jsp").bind("focusin.jsp",function(s){if(s.target===V[0]){return}Y(s.target,false)})}function D(){V.unbind("focusin.jsp")}function P(){var aF,s;C.attr("tabindex",0).unbind("keydown.jsp").bind("keydown.jsp",function(aJ){if(aJ.target!==C[0]){return}var aH=X,aG=H,aI=aF?2:16;switch(aJ.keyCode){case 40:S(H+aI,false);break;case 38:S(H-aI,false);break;case 34:case 32:J(aw()+Math.max(32,v)-16);break;case 33:J(aw()-v+16);break;case 35:J(W-v);break;case 36:J(0);break;case 39:T(X+aI,false);break;case 37:T(X-aI,false);break}if(!(aH==X&&aG==H)){aF=true;clearTimeout(s);s=setTimeout(function(){aF=false},260);return false}});if(au.hideFocus){C.css("outline","none");if("hideFocus" in aj[0]){C.attr("hideFocus",true)}}else{C.css("outline","");if("hideFocus" in aj[0]){C.attr("hideFocus",false)}}}function O(){C.attr("tabindex","-1").removeAttr("tabindex").unbind("keydown.jsp")}function B(){if(location.hash&&location.hash.length>1){var aG,aF;try{aG=b(location.hash)}catch(s){return}if(aG.length&&V.find(aG)){if(aj.scrollTop()==0){aF=setInterval(function(){if(aj.scrollTop()>0){Y(location.hash,true);b(document).scrollTop(aj.position().top);clearInterval(aF)}},50)}else{Y(location.hash,true);b(document).scrollTop(aj.position().top)}}}}function af(){b("a.jspHijack").unbind("click.jsp-hijack").removeClass("jspHijack")}function m(){af();b("a[href^=#]").addClass("jspHijack").bind("click.jsp-hijack",function(){var s=this.href.split("#"),aF;if(s.length>1){aF=s[1];if(aF.length>0&&V.find("#"+aF).length>0){Y("#"+aF,true);return false}}})}b.extend(N,{reinitialise:function(aF){aF=b.extend({},aF,au);an(aF)},scrollToElement:function(aG,aF,s){Y(aG,aF,s)},scrollTo:function(aG,s,aF){K(aG,aF);J(s,aF)},scrollToX:function(aF,s){K(aF,s)},scrollToY:function(s,aF){J(s,aF)},scrollBy:function(aF,s,aG){N.scrollByX(aF,aG);N.scrollByY(s,aG)},scrollByX:function(s,aG){var aF=ay()+s,aH=aF/(Q-ah);T(aH*j,aG)},scrollByY:function(s,aG){var aF=aw()+s,aH=aF/(W-v);S(aH*i,aG)},animate:function(aF,aI,s,aH){var aG={};aG[aI]=s;aF.animate(aG,{duration:au.animateDuration,ease:au.animateEase,queue:false,step:aH})},getContentPositionX:function(){return ay()},getContentPositionY:function(){return aw()},getIsScrollableH:function(){return aB},getIsScrollableV:function(){return av},getContentPane:function(){return V},scrollToBottom:function(s){S(i,s)},hijackInternalLinks:function(){m()}})}f=b.extend({},b.fn.jScrollPane.defaults,f);var e;this.each(function(){var g=b(this),h=g.data("jsp");if(h){h.reinitialise(f)}else{h=new d(g,f);g.data("jsp",h)}e=e?e.add(g):g});return e};b.fn.jScrollPane.defaults={showArrows:false,maintainPosition:true,clickOnTrack:true,autoReinitialise:false,autoReinitialiseDelay:500,verticalDragMinHeight:0,verticalDragMaxHeight:99999,horizontalDragMinWidth:0,horizontalDragMaxWidth:99999,animateScroll:false,animateDuration:300,animateEase:"linear",hijackInternalLinks:false,verticalGutter:4,horizontalGutter:4,mouseWheelSpeed:10,arrowButtonSpeed:10,arrowRepeatFreq:100,arrowScrollOnHover:false,trackClickSpeed:30,trackClickRepeatFreq:100,verticalArrowPositions:"split",horizontalArrowPositions:"split",enableKeyboardNavigation:true,hideFocus:false}})(jQuery,this);
//]]>
</script>

<script>
$(document).ready(function() {
$('.scroll-pane').jScrollPane({showArrows: true});
});
</script>

Luego busca la etiqueta:

<body>

O esta línea:

<body expr:class='&quot;loading&quot; + data:blog.mobileClass'>

Debajo de cualquiera de ellas dos agrega esto:

<div class='scroll-pane' id='blog-container'>

Por último busca la etiqueta </body> y arriba de ella pega esto:

</div>

Guarda los cambios y listo. En color verde verás dónde se cambian los colores de la barra de desplazamiento y sus diferentes áreas, como es CSS puedes añadirle otros estilos si lo deseas, somo sombras, bordes redondeados, etc.
Si quisieras que no aparezcan los límites superior e inferior (como en el ejemplo) entonces elimina lo que está en color rojo.

Recuerda que el script usa jQuery, así que si ya lo tuvieras no pongas de nuevo el script (la primera línea del código). Si usas Scriptaculous o Mootools deberás hacerle unos ligeros cambios para que funcione.

Parece largo el código pero siempre es mejor alojar los scripts directo en la plantilla que subirlo a un hosting, de estar forma los scripts siempre estarán disponibles y cargarán más rápido. Independientemente de todo eso el resultado final es bastante estético, ¿no lo creen?