HTML doesn't have a built-in editable dropdown list or combobox, but I implemented a mostly-CSS solution in an article.
You can see a full demo here but in summary, write HTML like this:
Apple
Banana
Cherry
Dewberry
And use CSS like this to style it (this is designed for both comboboxes, which have a down-arrow ▾ button, and dropdown menus which open when clicked and may be styled differently):
/* ------------------------------------------ */
/* ----- combobox / dropdown list styling */
/* ------------------------------------------ */
.combobox {
/* Border slightly darker than Chrome's , slightly lighter than FireFox's */
border: 1px solid #999;
padding-right: 1.25em; /* leave room for ▾ */
}
.dropdown, .combobox {
/* "relative" and "inline-block" (or just "block") are needed
here so that "absolute" works correctly in children */
position: relative;
display: inline-block;
}
.combobox > .downarrow, .dropdown > .downarrow {
/* ▾ Outside normal flow, relative to container */
display: inline-block;
position: absolute;
top: 0;
bottom: 0;
right: 0;
width: 1.25em;
cursor: default;
nav-index: -1; /* nonfunctional in most browsers */
border-width: 0px; /* disable by default */
border-style: inherit; /* copy parent border */
border-color: inherit; /* copy parent border */
}
/* Add a divider before the ▾ down arrow in non-dropdown comboboxes */
.combobox:not(.dropdown) > .downarrow {
border-left-width: 1px;
}
/* Auto-down-arrow if one is not provided */
.downarrow:empty::before {
content: '▾';
}
.downarrow::before, .downarrow > *:only-child {
text-align: center;
/* vertical centering trick */
position: relative;
top: 50%;
display: block; /* transform requires block/inline-block */
transform: translateY(-50%);
}
.combobox > input {
border: 0
}
.dropdown > *:last-child,
.combobox > *:last-child {
/* Using `display:block` here has two desirable effects:
(1) Accessibility: it lets input widgets in the dropdown to
be selected with the tab key when the dropdown is closed.
(2) It lets the opacity transition work.
But it also makes the contents visible, which is undesirable
before the list drops down. To compensate, use `opacity: 0`
and disable mouse pointer events. Another side effect is that
the user can select and copy the contents of the hidden list,
but don't worry, the selected content is invisible. */
display: block;
opacity: 0;
pointer-events: none;
transition: 0.4s; /* fade out */
position: absolute;
left: 0;
top: 100%;
border: 1px solid #888;
background-color: #fff;
box-shadow: 1px 2px 4px 1px #666;
box-shadow: 1px 2px 4px 1px #4448;
z-index: 9999;
min-width: 100%;
box-sizing: border-box;
}
/* List of situations in which to show the dropdown list.
- Focus dropdown or non-last child of it => show last-child
- Focus .downarrow of combobox => show last-child
- Stay open for focus in last child, unless .less-sticky
- .sticky last child stays open on hover
- .less-sticky stays open on hover, ignores focus in last-child */
.dropdown:focus > *:last-child,
.dropdown > *:focus ~ *:last-child,
.combobox > .downarrow:focus ~ *:last-child,
.combobox > .sticky:last-child:hover,
.dropdown > .sticky:last-child:hover,
.combobox > .less-sticky:last-child:hover,
.dropdown > .less-sticky:last-child:hover,
.combobox > *:last-child:focus:not(.less-sticky),
.dropdown > *:last-child:focus:not(.less-sticky) {
display: block;
opacity: 1;
transition: 0.15s;
pointer-events: auto;
}
/* focus-within not supported by Edge/IE. Unsupported selectors cause
the entire block to be ignored, so we must repeat all styles for
focus-within separately. */
.combobox > *:last-child:focus-within:not(.less-sticky),
.dropdown > *:last-child:focus-within:not(.less-sticky) {
display: block;
opacity: 1;
transition: 0.15s;
pointer-events: auto;
}
/* detect Edge/IE and behave if though less-sticky is on for all
dropdowns (otherwise links won't be clickable) */
@supports (-ms-ime-align:auto) {
.dropdown > *:last-child:hover {
display: block;
opacity: 1;
pointer-events: auto;
}
}
/* detect IE and do the same thing. */
@media all and (-ms-high-contrast: none), (-ms-high-contrast: active) {
.dropdown > *:last-child:hover {
display: block;
opacity: 1;
pointer-events: auto;
}
}
.dropdown:not(.sticky) > *:not(:last-child):focus,
.downarrow:focus, .dropdown:focus {
pointer-events: none; /* Causes second click to close */
}
.downarrow:focus {
outline: 2px solid #8BF; /* Edge/IE can't do outline transparency */
outline: 2px solid #48F8;
}
/* ---------------------------------------------- */
/* Optional extra styling for combobox / dropdown */
/* ---------------------------------------------- */
*, *:before, *:after {
/* See https://css-tricks.com/international-box-sizing-awareness-day/ */
box-sizing: border-box;
}
.combobox > *:first-child {
display: inline-block;
width: 100%;
box-sizing: border-box; /* so 100% includes border & padding */
}
/* `.combobox:focus-within { outline:...}` doesn't work properly
in Firefox because the focus box is expanded to include the
(possibly hidden) drop list. As a workaround, put focus box on
the focused child. It is barely-visible so that it doesn't look
TOO ugly if the child isn't the same size as the parent. It
may be uglier if the first child is not styled as width:100% */
.combobox > *:not(:last-child):focus {
outline: 2px solid #48F8;
}
.combobox {
margin: 5px;
}
You also need some JavaScript to synchronize the list with the textbox:
function parentComboBox(el) {
for (el = el.parentNode; el != null && Array.prototype.indexOf.call(el.classList, "combobox") <= -1;)
el = el.parentNode;
return el;
}
// Uses jQuery
$(".combobox.withtextlist > select").change(function() {
var textbox = parentComboBox(this).firstElementChild;
textbox.value = this[this.selectedIndex].text;
});
$(".combobox.withtextlist > select").keypress(function(e) {
if (e.keyCode == 13) // Enter pressed
parentComboBox(this).firstElementChild.focus(); // Closes the popup
});
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