例 5
これが、カスタムフォームウィジェットの作成方法を説明する最後の例です。
状態を変更する
HTML コンテンツ
<form class="no-widget">
<select name="myFruit">
<option>Cherry</option>
<option>Lemon</option>
<option>Banana</option>
<option>Strawberry</option>
<option>Apple</option>
</select>
<div class="select" role="listbox">
<span class="value">Cherry</span>
<ul class="optList hidden" role="presentation">
<li class="option" role="option" aria-selected="true">Cherry</li>
<li class="option" role="option">Lemon</li>
<li class="option" role="option">Banana</li>
<li class="option" role="option">Strawberry</li>
<li class="option" role="option">Apple</li>
</ul>
</div>
</form>
CSS コンテンツ
.widget select,
.no-widget .select {
position : absolute;
left : -5000em;
height : 0;
overflow : hidden;
}
/* --------------- */
/* Required Styles */
/* --------------- */
.select {
position: relative;
display : inline-block;
}
.select.active,
.select:focus {
box-shadow: 0 0 3px 1px #227755;
outline: none;
}
.select .optList {
position: absolute;
top : 100%;
left : 0;
}
.select .optList.hidden {
max-height: 0;
visibility: hidden;
}
/* ------------ */
/* Fancy Styles */
/* ------------ */
.select {
font-size : 0.625em; /* 10px */
font-family : Verdana, Arial, sans-serif;
box-sizing : border-box;
padding : 0.1em 2.5em 0.2em 0.5em; /* 1px 25px 2px 5px */
width : 10em; /* 100px */
border : 0.2em solid #000; /* 2px */
border-radius : 0.4em; /* 4px */
box-shadow : 0 0.1em 0.2em rgba(0,0,0,.45); /* 0 1px 2px */
background : #F0F0F0;
background : linear-gradient(0deg, #E3E3E3, #fcfcfc 50%, #f0f0f0);
}
.select .value {
display : inline-block;
width : 100%;
overflow : hidden;
white-space : nowrap;
text-overflow : ellipsis;
vertical-align: top;
}
.select:after {
content : "▼";
position: absolute;
z-index : 1;
height : 100%;
width : 2em; /* 20px */
top : 0;
right : 0;
padding-top : .1em;
box-sizing : border-box;
text-align : center;
border-left : .2em solid #000;
border-radius: 0 .1em .1em 0;
background-color : #000;
color : #FFF;
}
.select .optList {
z-index : 2;
list-style: none;
margin : 0;
padding: 0;
background: #f0f0f0;
border: .2em solid #000;
border-top-width : .1em;
border-radius: 0 0 .4em .4em;
box-shadow: 0 .2em .4em rgba(0,0,0,.4);
box-sizing : border-box;
min-width : 100%;
max-height: 10em; /* 100px */
overflow-y: auto;
overflow-x: hidden;
}
.select .option {
padding: .2em .3em;
}
.select .highlight {
background: #000;
color: #FFFFFF;
}
JavaScript コンテンツ
// -------------------- //
// Function definitions //
// -------------------- //
function deactivateSelect(select) {
if (!select.classList.contains('active')) return;
const optList = select.querySelector('.optList');
optList.classList.add('hidden');
select.classList.remove('active');
}
function activeSelect(select, selectList) {
if (select.classList.contains('active')) return;
selectList.forEach(deactivateSelect);
select.classList.add('active');
};
function toggleOptList(select, show) {
const optList = select.querySelector('.optList');
optList.classList.toggle('hidden');
}
function highlightOption(select, option) {
const optionList = select.querySelectorAll('.option');
optionList.forEach((other) => {
other.classList.remove('highlight');
});
option.classList.add('highlight');
};
function updateValue(select, index) {
const nativeWidget = select.previousElementSibling;
const value = select.querySelector('.value');
const optionList = select.querySelectorAll('.option');
optionList.forEach((other) => {
other.setAttribute('aria-selected', 'false');
});
optionList[index].setAttribute('aria-selected', 'true');
nativeWidget.selectedIndex = index;
value.innerHTML = optionList[index].innerHTML;
highlightOption(select, optionList[index]);
};
function getIndex(select) {
const nativeWidget = select.previousElementSibling;
return nativeWidget.selectedIndex;
};
// ------------- //
// Event binding //
// ------------- //
window.addEventListener("load", () => {
const form = document.querySelector('form');
form.classList.remove("no-widget");
form.classList.add("widget");
});
window.addEventListener('load', () => {
const selectList = document.querySelectorAll('.select');
selectList.forEach((select) => {
const optionList = select.querySelectorAll('.option');
const selectedIndex = getIndex(select);
select.tabIndex = 0;
select.previousElementSibling.tabIndex = -1;
updateValue(select, selectedIndex);
optionList.forEach((option, index) => {
option.addEventListener('mouseover', () => {
highlightOption(select, option);
});
option.addEventListener('click', (event) => {
updateValue(select, index);
});
});
select.addEventListener('click', (event) => {
toggleOptList(select);
});
select.addEventListener('focus', (event) => {
activeSelect(select, selectList);
});
select.addEventListener('blur', (event) => {
deactivateSelect(select);
});
select.addEventListener('keyup', (event) => {
let index = getIndex(select);
if (event.keyCode === 27) {
deactivateSelect(select);
}
if (event.keyCode === 40 && index < optionList.length - 1) {
index++;
}
if (event.keyCode === 38 && index > 0) {
index--;
}
updateValue(select, index);
});
});
});