How to force menu to open upwards in a searchable dropdown? - html

Question

I have an html code below
Dropdown-->
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Its basically taken from this website https://www.w3schools.com/howto/tryit.asp?filename=tryhow_css_js_dropdown_filter
This is how it looks like
It does a search on the items displayed in the menu. Now I want this menu to open upwards and not downwards
On looking online, I found I have to provide bottom: 100%; Drop-down menu that opens up/upward with pure css. Now in my case, there are no <ul> or <li> tags. So this is what I did
.dropdown {
position: relative;
display: inline-block;
bottom: 100%; //added this
}
But it doesn't do anything. How can I force the menu to show upwards?

Answer 1

You could do this using Flexbox:
.dropdown-content.show {
display: flex;
flex-direction: column-reverse;
bottom: 45px; /* hardcoded height of the button */
}
Using w3cschool's existing code:
/* When the user clicks on the button,
toggle between hiding and showing the dropdown content */
function myFunction() {
var dropdown, button;
dropdown = document.getElementById("myDropdown");
button = document.getElementById("myButton");
dropdown.classList.toggle("show");
dropdown.style.bottom = button.offsetHeight + "px";
}
function filterFunction() {
var input, filter, ul, li, a, i;
input = document.getElementById("myInput");
filter = input.value.toUpperCase();
div = document.getElementById("myDropdown");
a = div.getElementsByTagName("a");
for (i = 0; i < a.length; i++) {
txtValue = a[i].textContent || a[i].innerText;
if (txtValue.toUpperCase().indexOf(filter) > -1) {
a[i].style.display = "";
} else {
a[i].style.display = "none";
}
}
}
.dropbtn {
background-color: #4CAF50;
color: white;
padding: 16px;
font-size: 16px;
border: none;
cursor: pointer;
}
.dropbtn:hover,
.dropbtn:focus {
background-color: #3e8e41;
}
#myInput {
box-sizing: border-box;
background-image: url('searchicon.png');
background-position: 14px 12px;
background-repeat: no-repeat;
font-size: 16px;
padding: 14px 20px 12px 45px;
border: none;
border-bottom: 1px solid #ddd;
}
#myInput:focus {
outline: 3px solid #ddd;
}
.dropdown {
position: relative;
display: inline-block;
padding-top: 250px; /* just for demo purposes */
}
.dropdown-content {
display: none;
position: absolute;
background-color: #f6f6f6;
min-width: 230px;
overflow: auto;
border: 1px solid #ddd;
z-index: 1;
flex-direction: column-reverse; /* show children in a reversed colum (bottom to top) */
}
.dropdown-content a {
color: black;
padding: 12px 16px;
text-decoration: none;
display: block;
}
.dropdown a:hover {
background-color: #ddd;
}
.show {
display: flex;
}
<h2>Search/Filter Dropdown</h2>
<p>Click on the button to open the dropdown menu, and use the input field to search for a specific dropdown link.</p>
<div class="dropdown">
<button id="myButton" onclick="myFunction()" class="dropbtn">Dropdown</button>
<div id="myDropdown" class="dropdown-content">
<input type="text" placeholder="Search.." id="myInput" onkeyup="filterFunction()">
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Custom
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Tools
</div>
</div>
EDIT:
I just removed the hardcoded button height from the CSS and instead calculated the height using Javascript.
See the modified function myFunction() and the added id="myButton" in the markup.