Insert data using indexedDB in JavaScript

Insert data in using indexedDB. This is what i tried.

On page load am using ScriptManager to call a client side javascript function and passing 2 variables id_ and session_id_

String id_ = "10";
String session_id_ = System.Web.HttpContext.Current.Session.SessionID;
ScriptManager.RegisterStartupScript(this, GetType(), "", "add('" + id_ + "','" + session_id_ + "');", true);

The code works find when the 2 variables(id_,session_id_) are hardcoded and use onclick = "add()".

But when i run it as it is db.transaction(["user_session"], "readwrite") is underline says that Uncaught TypeError: Cannot read properties of undefined (reading 'transaction')

Javascript function

function add(id_, session_id_) {
    console.log(id_);
    console.log(session_id_);
    var request = db.transaction(["user_session"], "readwrite")
        .objectStore("user_session")
        .add({ id: id_, session_id: session_id_});
 
 
    request.onsuccess = function (event) {
        alert("data added successfully");
    };
 
    request.onerror = function (event) {
        alert("Unable to add data aready exist in database! ");
    }
}