Pass QueryString from one page to another using JavaScript

Hi jo15765,

Refer below example.

HTML

Default

<input type="text" id="txtId" />
<input type="button" value="Send" onclick="SendData()" />
<hr />
<span id="lblId" />
<script type="text/javascript">
    function SendData() {
        var id = document.getElementById("txtId").value;
        var popup = window.open("Popup.aspx?Id=" + id, "Popup", "width=300, height=100");
        popup.focus();
    }

    function GetData(data) {
        document.getElementById("lblId").innerHTML = data;
    }
</script>

Popup

<script type="text/javascript">
    if (window.opener != null && !window.opener.closed) {
        var id = location.search.split('=')[1];
        // Get data from API based on the Id.
        window.opener.GetData(parseInt(id) + 1);
        window.close();
    }
</script>

Screenshot