Accesibilidad para expandir la navegación con JavaScript y CSS3

Vista prévia

Descripción

Una navegación accesible animada que expande el botón de alternar menú de hamburguesa en un menú de navegación a pantalla completa cuando se conmuta.

Funcionamiento

Inserte el menú de navegación, el botón de alternancia de menú y el elemento de fondo en la Página Web.

<header class="header" role="banner">



<nav id="nav" class="nav" role="navigation">





<!-- ACTUAL NAVIGATION MENU -->


<ul class="nav__menu" id="menu" tabindex="-1" aria-label="main navigation" hidden>



<li class="nav__item"><a href="#" class="nav__link">Home</a></li>



<li class="nav__item"><a href="#" class="nav__link">Shop</a></li>



<li class="nav__item"><a href="#" class="nav__link">Blog</a></li>



<li class="nav__item"><a href="#" class="nav__link">About</a></li>



<li class="nav__item"><a href="#" class="nav__link">Contact</a></li>


</ul>





<!-- MENU TOGGLE BUTTON -->


<a href="#nav" class="nav__toggle" role="button" aria-expanded="false" aria-controls="menu">



<svg class="menuicon" xmlns="http://www.w3.org/2000/svg" width="50" height="50" viewBox="0 0 50 50">




<title>Toggle Menu</title>




<g>





<line class="menuicon__bar" x1="13" y1="16.5" x2="37" y2="16.5"/>





<line class="menuicon__bar" x1="13" y1="24.5" x2="37" y2="24.5"/>





<line class="menuicon__bar" x1="13" y1="24.5" x2="37" y2="24.5"/>





<line class="menuicon__bar" x1="13" y1="32.5" x2="37" y2="32.5"/>





<circle class="menuicon__circle" r="23" cx="25" cy="25" />




</g>



</svg>


</a>





<!-- ANIMATED BACKGROUND ELEMENT -->


<div class="splash"></div>




</nav>


</header>

Las reglas principales de CSS/CSS3 para la navegación.

.nav__toggle {

display: inline-block;

position: absolute;

z-index: 10;

padding: 0;

border: 0;

background: transparent;

outline: 0;

right: 15px;

top: 15px;

cursor: pointer;

border-radius: 50%;

-webkit-transition: background-color .15s linear;

transition: background-color .15s linear;
}

.nav__toggle:hover, .nav__toggle:focus { background-color: rgba(0, 0, 0, 0.5); }

.nav__menu {

display: -webkit-box;

display: -ms-flexbox;

display: flex;

-webkit-box-orient: vertical;

-webkit-box-direction: normal;

-ms-flex-direction: column;

flex-direction: column;

-webkit-box-pack: center;

-ms-flex-pack: center;

justify-content: center;

height: var(--screen-height);

position: relative;

z-index: 5;

visibility: hidden;
}

.nav__item {

opacity: 0;

-webkit-transition: all 0.3s cubic-bezier(0, 0.995, 0.99, 1) 0.3s;

transition: all 0.3s cubic-bezier(0, 0.995, 0.99, 1) 0.3s;
}

.nav__item:nth-child(1) {

-webkit-transform: translateY(-40px);

transform: translateY(-40px);
}

.nav__item:nth-child(2) {

-webkit-transform: translateY(-80px);

transform: translateY(-80px);
}

.nav__item:nth-child(3) {

-webkit-transform: translateY(-120px);

transform: translateY(-120px);
}

.nav__item:nth-child(4) {

-webkit-transform: translateY(-160px);

transform: translateY(-160px);
}

.nav__item:nth-child(5) {

-webkit-transform: translateY(-200px);

transform: translateY(-200px);
}

.nav__link {

color: white;

display: block;

text-align: center;

text-transform: uppercase;

letter-spacing: 5px;

font-size: 1.25rem;

text-decoration: none;

padding: 1rem;
}

.nav__link:hover, .nav__link:focus {

outline: 0;

background-color: rgba(0, 0, 0, 0.2);
}

.menuicon {

display: block;

cursor: pointer;

color: white;

-webkit-transform: rotate(0deg);

transform: rotate(0deg);

-webkit-transition: 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);

transition: 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
}

.menuicon__bar, .menuicon__circle {

fill: none;

stroke: currentColor;

stroke-width: 3;

stroke-linecap: round;
}

.menuicon__bar {

-webkit-transform: rotate(0deg);

transform: rotate(0deg);

-webkit-transform-origin: 50% 50%;

transform-origin: 50% 50%;

-webkit-transition: -webkit-transform .25s ease-in-out;

transition: -webkit-transform .25s ease-in-out;

transition: transform .25s ease-in-out;

transition: transform .25s ease-in-out, -webkit-transform .25s ease-in-out;
}

.menuicon__circle {

-webkit-transition: stroke-dashoffset .3s linear .1s;

transition: stroke-dashoffset .3s linear .1s;

stroke-dashoffset: 144.51326;

stroke-dasharray: 144.51326;
}

.splash {

position: absolute;

top: 40px;

right: 40px;

width: 1px;

height: 1px;
}

.splash::after {

content: "";

display: block;

position: absolute;

border-radius: 50%;

background-color: var(--splash-bg-color);

width: 284vmax;

height: 284vmax;

top: -142vmax;

left: -142vmax;

-webkit-transform: scale(0);

transform: scale(0);

-webkit-transform-origin: 50% 50%;

transform-origin: 50% 50%;

-webkit-transition: -webkit-transform 0.5s cubic-bezier(0.755, 0.05, 0.855, 0.06);

transition: -webkit-transform 0.5s cubic-bezier(0.755, 0.05, 0.855, 0.06);

transition: transform 0.5s cubic-bezier(0.755, 0.05, 0.855, 0.06);

transition: transform 0.5s cubic-bezier(0.755, 0.05, 0.855, 0.06), -webkit-transform 0.5s cubic-bezier(0.755, 0.05, 0.855, 0.06);

will-change: transform;
}

.nav:target > .splash::after, .nav--open > .splash::after {

-webkit-transform: scale(1);

transform: scale(1);
}

.nav:target .menuicon, .nav--open .menuicon {

color: white;

-webkit-transform: rotate(180deg);

transform: rotate(180deg);
}

.nav:target .menuicon__circle, .nav--open .menuicon__circle { stroke-dashoffset: 0; }

.nav:target .menuicon__bar:nth-child(1), .nav:target .menuicon__bar:nth-child(4), .nav--open .menuicon__bar:nth-child(1), .nav--open .menuicon__bar:nth-child(4) { opacity: 0; }

.nav:target .menuicon__bar:nth-child(2), .nav--open .menuicon__bar:nth-child(2) {

-webkit-transform: rotate(45deg);

transform: rotate(45deg);
}

.nav:target .menuicon__bar:nth-child(3), .nav--open .menuicon__bar:nth-child(3) {

-webkit-transform: rotate(-45deg);

transform: rotate(-45deg);
}

.nav:target .nav__menu, .nav--open .nav__menu { visibility: visible; }

.nav:target .nav__item, .nav--open .nav__item {

opacity: 1;

-webkit-transform: translateY(0);

transform: translateY(0);
}

El JavaScript para activar la navegación.

'use strict';

var nav = document.querySelector('#nav');
var menu = document.querySelector('#menu');
var menuToggle = document.querySelector('.nav__toggle');
var isMenuOpen = false;

// TOGGLE MENU ACTIVE STATE
menuToggle.addEventListener('click', function (e) {

e.preventDefault();

isMenuOpen = !isMenuOpen;


// toggle a11y attributes and active class

menuToggle.setAttribute('aria-expanded', String(isMenuOpen));

menu.hidden = !isMenuOpen;

nav.classList.toggle('nav--open');
});

// TRAP TAB INSIDE NAV WHEN OPEN
nav.addEventListener('keydown', function (e) {

// abort if menu isn't open or modifier keys are pressed

if (!isMenuOpen || e.ctrlKey || e.metaKey || e.altKey) {


return;

}


// listen for tab press and move focus

// if we're on either end of the navigation

var menuLinks = menu.querySelectorAll('.nav__link');

if (e.keyCode === 9) {


if (e.shiftKey) {



if (document.activeElement === menuLinks[0]) {




menuToggle.focus();




e.preventDefault();



}


} else if (document.activeElement === menuToggle) {



menuLinks[0].focus();



e.preventDefault();


}

}
});