Q:

How to get the search box value in  tag - HTML,JS

Am new to javascript i foud this one in w3schools.com -  Entering pincode in search box will show in <p> tag !!  How to do ?  any help appreciated.  Thanks in advance 
HTML :
<form class="form1" role="search" method="get" action="search-pincode.html">
<input class="pincode1" type="number" placeholder="Enter Postcode" id="user-pincode">
<button class="submit" type="submit" formaction="search-pincode.html" onclick="myFunction()">Check</button>
</form>

JS SCRIPT :
    <script>
    function myFunction() {
    var x = document.getElementById("user-pincode").value;
    document.getElementById("user-pincode-show").innerHTML = x;
    }
    </script>

OUTPUT : search-pincode.html
                <h1 class="search-h1-contact">
                Yes, we install CCTV in <p id="user-pincode-show"></p>
                </h1>

A:

For one, you will not see the result long enough because after clicking the button, you are being redirected to search-pincode.html.  Try changing type="submit" to type="button"

function myFunction() {
  var x = document.getElementById("user-pincode").value;
  document.getElementById("user-pincode-show").innerHTML = x;
}
<form class="form1" role="search" method="get" action="search-pincode.html">
  <input type="number" placeholder="Enter Postcode" id="user-pincode">
  <button type="button" onclick="myFunction()">Check</button>
</form>

<h1 class="search-h1-contact">
  Yes, we install CCTV in
  <p id="user-pincode-show"></p>
</h1>

If what you are planning is to pass the value of the input to search-pincode.html, and user-pincode-show is inside it, then using JavaScript is not proper way to do it

