Hi,
Seeking your help.
Given below is a code taken from Other sources. I tried however not able to amend it.
I am trying for image gallery which will have 2 types of filters
1) Based on navigation
2) based on the content mentioned in the input box.

Request you to please help

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
* {
box-sizing: border-box;
}

body {
background-color: #f1f1f1;
padding: 20px;
font-family: Arial;
}

/* Center website */
.main {
max-width: 1000px;
margin: auto;
}

h1 {
font-size: 50px;
word-break: break-all;
}

.row {
margin: 10px -16px;
}

/* Add padding BETWEEN each column */
.row,
.row > .column {
padding: 8px;
}

/* Create three equal columns that floats next to each other */
.column {
float: left;
width: 19.99%;
display: none; /* Hide all elements by default */
}

/* Clear floats after rows */
.row:after {
content: "";
display: table;
clear: both;
}

/* Content */
.content {
background-color: white;
padding: 10px;
}

/* The "show" class is added to the filtered elements */
.show {
display: block;
}

/* Style the buttons */
.btn {
border: none;
outline: none;
padding: 12px 16px;
background-color: white;
cursor: pointer;
}

.btn:hover {
background-color: #ddd;
}

.btn.active {
background-color: #666;
color: white;
}
</style>
</head>
<body>

<!-- MAIN (Center website) -->
<div class="main">

<h1>MYLOGO.COM</h1>
<hr>
<input type="text" id="myInput" onkeyup="myFunction()" placeholder="Search for Content" title="Search">
<h2>PORTFOLIO</h2>

<div id="myBtnContainer">
<button class="btn active" onclick="filterSelection('all')"> Show all</button>
<button class="btn" onclick="filterSelection('nature')"> Nature</button>
<button class="btn" onclick="filterSelection('cars')"> Cars</button>
<button class="btn" onclick="filterSelection('people')"> People</button>
</div>

<!-- Portfolio Gallery Grid -->
<div class="row mysrch">
<div class="column nature">
<div class="content">
<img src="Growth.png" alt="Mountains" style="width:100%">
<h4>Mountains</h4>
<p>Lorem ipsum dolor..</p>
</div>
</div>
<div class="column cars">
<div class="content">
<img src="CogWheel.png" alt="Lights" style="width:100%">
<h4>Lights</h4>
<p>Lorem ipsum dolor..</p>
</div>
</div>
<div class="column cars">
<div class="content">
<img src="Growth.png" alt="Nature" style="width:100%">
<h4>Forest</h4>
<p>Lorem ipsum dolor..</p>
</div>
</div>

<div class="column cars">
<div class="content">
<img src="CogWheel.png" alt="Car" style="width:100%">
<h4>Retro</h4>
<p>Lorem ipsum dolor..</p>
</div>
</div>
<div class="column cars">
<div class="content">
<img src="Growth.png" alt="Car" style="width:100%">
<h4>Fast</h4>
<p>Lorem ipsum dolor..</p>
</div>
</div>
<div class="column people">
<div class="content">
<img src="CogWheel.png" alt="Car" style="width:100%">
<h4>Classic</h4>
<p>Lorem ipsum dolor..</p>
</div>
</div>

<div class="column people">
<div class="content">
<img src="Offer.png" alt="Car" style="width:100%">
<h4>Girl</h4>
<p>Lorem ipsum dolor..</p>
</div>
</div>
<div class="column people">
<div class="content">
<img src="Offer.png" alt="Car" style="width:100%">
<h4>Man</h4>
<p>Lorem ipsum dolor..</p>
</div>
</div>
<div class="column people">
<div class="content">
<img src="Offer.png" alt="Car" style="width:100%">
<h4>Woman</h4>
<p>Lorem ipsum dolor..</p>
</div>
</div>
<!-- END GRID -->
</div>

<!-- END MAIN -->
</div>

<script>
function myFunction() {
var input, filter, div, p, i, txtValue;
input = document.getElementById("myInput");
filter = input.value.toUpperCase();
ul = document.getElementById("mysrch");
li = div.getElementsByTagName("p");
for (i = 0; i < li.length; i++) {
a = li[i].getElementsByTagName("a")[0];
txtValue = a.textContent || a.innerText;
if (txtValue.toUpperCase().indexOf(filter) > -1) {
li[i].style.display = "";
} else {
li[i].style.display = "none";
}
}
}
</script>
<script>
filterSelection("all")
function filterSelection© {
var x, i;
x = document.getElementsByClassName("column");
if (c == "all") c = "";
for (i = 0; i < x.length; i++) {
w3RemoveClass(x[i], "show");
if (x[i].className.indexOf© > -1) w3AddClass(x[i], "show");
}
}

function w3AddClass(element, name) {
var i, arr1, arr2;
arr1 = element.className.split(" ");
arr2 = name.split(" ");
for (i = 0; i < arr2.length; i++) {
if (arr1.indexOf(arr2[i]) == -1) {element.className += " " + arr2[i];}
}
}

function w3RemoveClass(element, name) {
var i, arr1, arr2;
arr1 = element.className.split(" ");
arr2 = name.split(" ");
for (i = 0; i < arr2.length; i++) {
while (arr1.indexOf(arr2[i]) > -1) {
arr1.splice(arr1.indexOf(arr2[i]), 1);
}
}
element.className = arr1.join(" ");
}


// Add active class to the current button (highlight it)
var btnContainer = document.getElementById("myBtnContainer");
var btns = btnContainer.getElementsByClassName("btn");
for (var i = 0; i < btns.length; i++) {
btns[i].addEventListener("click", function(){
var current = document.getElementsByClassName("active");
current[0].className = current[0].className.replace(" active", "");
this.className += " active";
});
}
</script>



</body>
</html>